<?xml version="1.0"?>
<xsl:stylesheet version="1.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xhtml="http://www.w3.org/1999/xhtml"
    xmlns="http://www.w3.org/1999/xhtml"
    exclude-result-prefixes="xhtml">
    
    <xsl:output indent="yes" method="html"
        doctype-system="http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" 
        doctype-public="-//W3C//DTD XHTML 1.0 Transitional//EN" />

    <!-- Dereference the rel="subsection" hyperlinks -->
    <xsl:template match="xhtml:a[@rel='subsection']">
        <xsl:for-each select="document(./@href)/xhtml:html/xhtml:body">
            <xsl:apply-templates />
        </xsl:for-each>
    </xsl:template>

    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>