position behavior in nested grouping

Hai,

I am having the input like below:

<articles>
      <row>
         <col>627</col>
         <col>Abstracts of the Series of Fascia Congress - Part 4</col>
         <col>270</col>
      </row>
      <row>
         <col>661</col>
         <col>Abstracts of the Series of Fascia Congress - Part 4</col>
         <col>270</col>
      </row>
      <row>
         <col>676</col>
         <col>Abstracts of the Series of Fascia Congress - Part 4</col>
         <col>271</col>
      </row>
      <row>
         <col>719</col>
         <col>Abstracts of the Series of Fascia Congress - Part 4</col>
         <col>272</col>
      </row>
      <row>
         <col>706</col>
         <col>Prevention &amp; Rehabilitation|Editorial</col>
         <col>276</col>
      </row>
      <row>
         <col>690</col>
         <col>Prevention &amp; Rehabilitation|Editorial</col>
         <col>283</col>
      </row>
      <row>
         <col>721</col>
         <col>Prevention &amp; Rehabilitation|Learning Methodology</col>
         <col>291</col>
      </row>
   </articles>


My expected output is as follows:

			<sections>
                               <section-title>Contents</section-title>
                           <section>
				<section-head>Abstracts of the Series of Fascia Congress - Part
4</section-head>
				<para>
					<page>270</page>
				</para>
				<para>
					<page>271</page>
				</para>
				<para>
					<page>271</page>
				</para>
				<para>
					<page>272</page>
				</para>
			</section>
			<section>
				<section-head>Prevention &amp; Rehabilitation</section-head>
				<section-subhead>Editorial</section-subhead>
				<para>
					<page>273</page>
				</para>
				<para>
					<page>277</page>
				</para>
			</section>
			<section>
				<section-subhead>Learning Methodology</section-subhead>
				<para>
					<page>284</page>
				</para>
			</section>
		</sections>

My code is as follows:

	<xsl:template match="articles">
			<sections>
				<section-title>Contents</section-title>
				<xsl:for-each-group select="row" group-by="col[2]">
					<xsl:variable name="head"
select="substring-before(current-grouping-key(),'&#x0007C;')"/>
					<section>
						<xsl:choose>
							<xsl:when test="contains(current-grouping-key(),'&#x0007C;')">
								<xsl:for-each-group select="current-group()"
group-by="substring-after(current-grouping-key(),'&#x0007C;')">
         						<xsl:if test="position()=1">
                                                         <section-head>
									<xsl:value-of select="$head"/>
							</section-head>
                                                        </xsl:if>
							<section-subhead>
										<xsl:value-of select="current-grouping-key()"/>
									</section-subhead>
									<xsl:apply-templates select="current-group()"/>
								</xsl:for-each-group>
							</xsl:when>
							<xsl:otherwise>
								<section-head>
									<xsl:value-of select="current-grouping-key()"/>
								</section-head>
								<xsl:apply-templates select="current-group()"/>
							</xsl:otherwise>
						</xsl:choose>
					</section>
				</xsl:for-each-group>
			</sections>
	</xsl:template>

The output of this code is as follows:

                      <sections>
			<section>
				<section-head>Abstracts of the Series of Fascia Congress - Part
4</section-head>
				<para>
					<page>270</page>
				</para>
				<para>
					<page>270</page>
				</para>
				<para>
					<page>271</page>
				</para>
				<para>
					<page>272</page>
				</para>
			</section>
			<section>
				<section-head>Prevention &amp; Rehabilitation</section-head>
				<section-subhead>Editorial</section-subhead>
				<para>
					<page>276</page>
				</para>
				<para>
					<page>283</page>
				</para>
			</section>
			<section>
				<section-head>Prevention &amp; Rehabilitation</section-head>
				<section-subhead>Learning Methodology</section-subhead>
				<para>
					<page>291</page>
				</para>
			</section>
		</sections>

Problem:

<section-head> should come only in the first group and should not come
in the second group. When I use position() in outer group I am getting
the correct value of the position but when I use position() in
nested/inner group the value is always 1. How to achieve the correct
position value in the nested/inner group.

Regards,
Ganesh