Identity Transform Grouping Question

   I have an identity transform that attempts to group elements at a deeply
nested level, but I am having trouble accomplishing this.  The xslt performs
the identity transform and sorts the result tree on a few levels, all
successfully.  The problem occurs when I attempt the deep-level grouping.

Given the following source tree sample:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="offices.xsl" ?>
<locations version="1.0">
   <divisions>
      <division id="B">
         <regions>
            <region name="europe">
               <countries>
                  <country name="England">
                     <offices>
                        <office id="BR4">
                           <names>
                              <name lang='en'>Branch 4</name>
                           </names>
                           <address>
                              <line>26 Abbey Lane</line>
                              <line>London</line>
                           </address>
                           <cities>
                              <city>London</city>
                           </cities>
                           <phone>+44-22-2222 2222</phone>
                        </office>
                        <office id="BR5">
                           <names>
                              <name lang='en'>AAAAA Branch 4</name>
                           </names>
                           <address>
                              <line>7 Kings Highway</line>
                              <line>London</line>
                           </address>
                           <cities>
                              <city>London</city>
                           </cities>
                           <phone>+44-99-9999 9999</phone>
                        </office>
                        <office id="BR6">
                           <names>
                              <name lang='en'>Branch 4</name>
                           </names>
                           <address>
                              <line>22 Abbey Lane</line>
                              <line>London</line>
                           </address>
                           <cities>
                              <city>London</city>
                           </cities>
                           <phone>+44-55-555 5555</phone>
                        </office>
                     </offices>
                  </country>
               </countries>
            </region>
         </regions>
      </division>
   </divisions>
</locations>

...the xslt should produce the following result tree:

<?xml version="1.0" encoding="UTF-8"?>
<locations>
   <divisions>
      <division id="B">
         <regions>
            <region name="europe">
               <countries>
                  <country name="England">
                     <cities>
                        <city>
                           <name>London</name>
                           <offices>
                              <office>
                                 <names>
                                    <name lang='en'>AAAAA Branch 4</name>
                                 </names>
                                 <location>
                                   <address>
                                       <line>7 Kings Highway</line>
                                       <line>London</line>
                                    </address>
                                    <phone>+44-99-9999 9999</phone>
                                 </location>
                              </office>
                              <office>
                                 <names>
                                    <name lang='en'>Branch 4</name>
                                 </names>
                                 <location>
                                    <address>
                                       <line>22 Abbey Lane</line>
                                       <line>London</line>
                                    </address>
                                    <phone>+44-55-555 5555</phone>
                                 </location>
                                 <location>
                                    <address>
                                       <line>26 Abbey Lane</line>
                                       <line>London</line>
                                    </address>
                                    <phone>+44-22-2222 2222</phone>
                                 </location>
                              </office>
                           </offices>
                        </city>
                     </cities>
                  </country>
               </countries>
            </region>
         </regions>
      </division>
   </divisions>
</locations>

  The <office> elements contain all child elements where the
office/names/name[@lang='en'] values match.  Further, a new element --
<location> has been added as a child to <office>.  The goal is to have only
one <names> element under an <office> element for each unique occurrence of
names/name where @lang='en' -- in other words, group all office locations by
their common English office name, then copy all location-specific information
for each office to the result tree as new <location> elements underneath the
<office> element.

  My current XSLT is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:key name="by-city" match="temp/office/cities/city" use="."/>

<xsl:template match="/">
   <locations>
      <divisions>
         <xsl:for-each select="locations/divisions/division">
            <xsl:sort select="@id"/>
            <division id="{@id}">
               <regions>
                  <xsl:for-each select="regions/region">
                     <xsl:sort select="@name"/>
                     <region name="{@name}">
                        <countries>
                           <xsl:for-each select="countries/country">
                              <xsl:sort select="@name"/>
                              <country name="{@name}">
                                 <xsl:variable name="rtf">
                                    <temp>
                                       <xsl:copy-of select="offices/office"/>
                                    </temp>
                                 </xsl:variable>
                                 <xsl:for-each
select="msxsl:node-set($rtf)/temp/office/cities/city[generate-id(.) =
generate-id(key('by-city', .)[1])]">
                                    <xsl:sort select="."/>
                                    <cities>
                                       <city>
                                          <name>
                                             <xsl:value-of select="."/>
                                          </name>
                                          <offices>
                                                <xsl:for-each
select="key('by-city', .)">
                                                   <xsl:sort
select="../../names/name[@lang='en']"/>
                                                   <xsl:sort
select="../../address"/>
                                                <xsl:if
test="../../names/name[@lang='en']
!=../../preceding-sibling::names/name[@lang='en']">
                                                <!-- <office>  new <office>
element should be inserted here -->
                                                      <xsl:copy-of
select="../../names"/>
                                                </xsl:if>
                                                   <location>
                                                      <xsl:copy-of
select="../preceding-sibling::address"/>
                                                      <xsl:copy-of
select="../following-sibling::phone"/>
                                                   </location>
                                                <!-- </office>  if the current
node is the last in a group with the same /names/name[@lang='en'] value,
                                                                    then
closing tag should be inserted here -->
                                                </xsl:for-each>
                                          </offices>
                                       </city>
                                    </cities>
                                 </xsl:for-each>
                              </country>
                           </xsl:for-each>
                        </countries>
                     </region>
                  </xsl:for-each>
               </regions>
            </division>
         </xsl:for-each>
      </divisions>
   </locations>
</xsl:template>
</xsl:stylesheet>

...and my result tree looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<locations>
   <divisions>
      <division id="B">
         <regions>
            <region name="europe">
               <countries>
                  <country name="England">
                     <cities>
                        <city>
                           <name>London</name>
                           <offices>
                              <location>
                                 <address>
                                    <line>7 Kings Highway</line>
                                    <line>London</line>
                                 </address>
                                 <phone>+44-99-9999 9999</phone>
                              </location>
                              <location>
                                 <address>
                                    <line>22 Abbey Lane</line>
                                    <line>London</line>
                                 </address>
                                 <phone>+44-55-555 5555</phone>
                              </location>
                              <location>
                                 <address>
                                    <line>26 Abbey Lane</line>
                                    <line>London</line>
                                 </address>
                                 <phone>+44-22-2222 2222</phone>
                              </location>
                           </offices>
                        </city>
                     </cities>
                  </country>
               </countries>
            </region>
         </regions>
      </division>
   </divisions>
</locations>

   The missing pieces are unique <names> elements (selected according to the
above-specified criteria) and the appropriate placement of <office> elements
(encapsulating <names> and <location> elements).

   I appreciate any help that can be offered!


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