[xsl] Grouping problem

[Terry Ofner <tofner@xxxxxxxxxxx>]

Dear xsl-list,

I am attempting to group the following using XSLT 2.0. Here is a  
snippet of the XML (edited for readability):

<?xml version="1.0"?>
<Root>
<State>
	<!--first standard; first lesson-->
	<Standard>
		<SS id="1.4.1">1.4.1  standard text </SS>
		<Lesson>Prefixes and Suffixes</Lesson>
	</Standard>

	<!--same standard as first; new lesson-->
	<Standard>
		<SS id="1.4.1">1.4.1  standard text</SS>
		<Lesson>Root Words</Lesson>
	</Standard>

	<!--new standard; new lesson-->	
	<Standard>
		<SS id="1.4.2">1.4.2  standard text</SS>
		<Lesson>Context Clues</Lesson>
	</Standard>

	<!--two standards grouped with one lesson-->	
	<Standard>
		<SS id="1.4.5">1.4.5  standard text/SS>
	        <SS id="1.4.6">1.4.6  standard text</SS>
		<Lesson>Synonyms</Lesson>
	</Standard>	
	. . .
</State>
</Root>

Here is what I am seeking:

	<!--Lessons grouped after common standard-->

	<Standard>
		<SS id="1.4.1">1.4.1  standard text </SS>
		<Lesson>Prefixes and Suffixes</Lesson>
		<Lesson>Root Words</Lesson>
	</Standard>

	. . .

	<!--grouped standards separated-->

	<Standard>
		<SS id="1.4.5">1.4.5  standard text </SS>
		<Lesson>Synonyms</Lesson>
	</Standard>
	<Standard>
	        <SS id="1.4.6">1.4.6  new standard grouped with preceeding  
sibling</SS>
		<Lesson>Synonyms</Lesson>
	</Standard>

So far I have been able to group the <SS> elements using for-each-group:

<xsl:stylesheet version="2.0"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
<xsl:output method="xml" indent="no"/>

<xsl:template match="State">
  <xsl:for-each-group select="Standard/SS" group-by="@id">
      <xsl:for-each select="current-group()"/>
      <xsl:copy-of select="."/><xsl:text>&#10;</xsl:text>
      </xsl:for-each-group>
      </xsl:template>
</xsl:stylesheet>


When I try to work in the <Lesson> elements, I get the entire  
standards listing.
I have also wondered if I need to first separate the grouped standards.

Any help would be appreciated.

Terry