XSL : Report Grouping Problem

Dear All XSL expert,

I hava a input xml data source which I need to format it to a nicely
grouped report.
I am using xalan to do the XSLT.

I have to do the grouping by Service, then ExCode+ExName, then Date+CCY.
In my first sight, I use several for-loop in my XSL to do this.
First loop all the distinct Service node and
      then loop all distinct Item[ExCode+ExName] and
          then loop all distinct Item[Date+CCY} and
               then loop all item[Service+(ExCode+ExName)+(Date+CCY)]
+++++++++++
XML Source:
+++++++++++
<Data>
     <Item>
          <Service>M</Service>
          <ExCode>A</ExCode>
          <ExName>Exchange A</ExName>
          <Ref>A</Ref>
          <Date>20001221</Date>
          <CCY>HKD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>A</ExCode>
          <ExName>Exchange A</ExName>
          <Ref>B</Ref>
          <Date>20001221</Date>
          <CCY>HKD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>A</ExCode>
          <ExName>Exchange A</ExName>
          <Ref>C</Ref>
          <Date>20001222</Date>
          <CCY>HKD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>A</ExCode>
          <ExName>Exchange A</ExName>
          <Ref>D</Ref>
          <Date>20001222</Date>
          <CCY>HKD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>A</ExCode>
          <ExName>Exchange A</ExName>
          <Ref>E</Ref>
          <Date>20001222</Date>
          <CCY>USD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>A</ExCode>
          <ExName>Exchange A</ExName>
          <Ref>F</Ref>
          <Date>20001222</Date>
          <CCY>USD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>B</ExCode>
          <ExName>Exchange B</ExName>
          <Ref>G</Ref>
          <Date>20001222</Date>
          <CCY>HKD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>M</Service>
          <ExCode>B</ExCode>
          <ExName>Exchange B</ExName>
          <Ref>H</Ref>
          <Date>20001222</Date>
          <CCY>HKD</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>C</Service>
          <ExCode>C</ExCode>
          <ExName>Exchange C</ExName>
          <Ref>I</Ref>
          <Date>20001230</Date>
          <CCY>YEN</CCY>
          <Amt>1000.00</Amt>
     </Item>
     <Item>
          <Service>C</Service>
          <ExCode>C</ExCode>
          <ExName>Exchange C</ExName>
          <Ref>J</Ref>
          <Date>20001230</Date>
          <CCY>YEN</CCY>
          <Amt>1000.00</Amt>
     </Item>
</Data>
+++++++++++++++
Expected Ouput :
+++++++++++++++
          Date      Ref  Currency  Amount
==================================================================
Service Type : M
     Exchange Code & Desc : A , Exchange A
          20001221            A    HKD                      1000.00
          20001221            B    HKD                      1000.00

          20001222           C     HKD                      1000.00
          20001222           D     HKD                      1000.00

          20001222            E    USD                      1000.00
          20001222            F    USD                      1000.00

     Exchange Code & Desc : B , Exchange B
          20001221          G  HKD                      1000.00
          20001221           H      HKD                      1000.00

Service Type : C
     Exchange Code & Desc :C , Exchange C
          20001230       I          YEN                      1000.00
          20001230       J          YEN                     1000.00

+++++++++++++++
my XSL scriplet
+++++++++++++++
<xsl:variable name="dist_service"
select="//Service[not(.=preceding::Service]"/>
<xsl:key name="exchange" match="Data use="concat(ExCode, ' ',ExName)"/>
<xsl:key name="date_ccy" match="Data" use="concat(CCY, ' ',Date)"/>

<xsl:template match="Data">
     <xsl:for-each select="$dist_service">
          <xsl:variable name="this_service" select="."/>
          <xsl:value-of select="$this_service"/>
          <xsl:for-each
select="//Item[count(key("exchange",concat(ExCode,'',ExName))[1] | . )=1]">
<<--- is there way I can select distinct "exchange" with
Service=$this_service?
               <xsl:variable name="this_excode" select="ExCode"/>
               <xsl:variable name="this_exname" select="ExName"/>
               <xsl:value-of select="$this_excode"/>
               <xsl:value-of select="$this_exname"/>
               <xsl:for-each
select="//Item[count(key("date_ccy",concat(CCY,'',Date))[1] | . )=1]">
                    <xsl:variable name="this_ccy" select="CCY"/>
                    <xsl:variable name="this_date" select="Date"/>
                    <xsl:for-each select="//Item[Service=$this_service and
ExCode=$this_excode and ExName=this_exname and CCY=$ths_ccy and
Date=$this_date]">
                         <xsl:value-of select="Date">
                         <xsl:value-of select="Ref">
                         <xsl:value-of select="CCY">
                         <xsl:value-of select="Amt">
                    </xsl:for-each>
               </xsl:for-each>
          </xsl:for-each>
     </xsl:for-each>
</xsl:template>

?????? However what I got is
     Service Type M
               A, Exchange A
                    ...  .....     ....
               B, Exchange B
                    .... .....          ......
               C, Exchange C  <<<<<--- I do not want this

     Service Type C
               A, Exchange A  <<<<<--- I do not want this
               B, Exchange B  <<<<<--- I do not want this
               C, Exchange C
                    .....   ........ ....................

Would someone please help to correct my xsl please ?

Many Thanks.




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