[xsl] grouping with xsl:for-each-group

[gregor FELLENZ <gregor@xxxxxxxxxxxx>]

hi there,

i've got a flat xml document and need some hierachy in there. the first 
approach was promising, but now i'm stuck how to fix the last bit.
i think i could do a procedural style, but i guess theres an elegant 
solution for the problem.

i would like to put any group of "einschub" elements in a separate 
container. this works fine when there's an other element inbetween. but 
fails with different "einschub" sibling-elements.

step by step:
1. source doc:
<kapitel>
    <abs>abs</abs>
    <einschub1>einschub1</einschub1>
    <einschub1>einschub1</einschub1>
    <abs>abs</abs>
    <einschub1>einschub1</einschub1>
    <einschub2>einschub2</einschub2>
    <abs>abs</abs>
    <abs>abs</abs>
</kapitel>

2. xslt
<xsl:template match="kapitel">
    <xsl:element name="kapitel">
        <xsl:for-each-group select="*" 
group-adjacent="starts-with(local-name(),'einschub')" >
            <xsl:choose>
                <xsl:when test="current-grouping-key()">
                    <xsl:element name="einschub">
                        <xsl:attribute name="typ" 
select='replace(local-name(), "[^\d]+", "")'/>
                        <xsl:apply-templates select="current-group()"/>
                    </xsl:element>
                </xsl:when>
                <xsl:otherwise>
                    <xsl:apply-templates select="current-group()"/>
                </xsl:otherwise>
            </xsl:choose>
        </xsl:for-each-group>
    </xsl:element>
</xsl:template>

<xsl:template match="einschub1|einschub2">
        <xsl:element name="abs">
            <xsl:apply-templates/>
        </xsl:element>
</xsl:template>

3. output with saxon9
<kapitel>
    <abs>abs</abs>
    <einschub typ="1">
        <abs>einschub1</abs>
        <abs>einschub1</abs>
    </einschub>
    <abs>abs</abs>
    <einschub typ="1">
        <abs>einschub1</abs>
        <abs>einschub2</abs>
    </einschub>
    <abs>abs</abs>
    <abs>abs</abs>
</kapitel>


4. desired output
<kapitel>
    <abs>abs</abs>
    <einschub typ="1">
        <abs>einschub1</abs>
        <abs>einschub1</abs>
    </einschub>
    <abs>abs</abs>
    <einschub typ="1">
        <abs>einschub1</abs>
    </einschub>
    <einschub typ="2">
        <abs>einschub2</abs>
    </einschub>
    <abs>abs</abs>
    <abs>abs</abs>
</kapitel>

any help is greatly appreciated!


all the best,
gregor