Re: XSLT2: Keys vs. xsl:choose to distinguish groups

Why not use apply-templates to despatch based on the first member of the
group:

<xsl:for-each-group....
  <xsl:apply-templates select="current-group()[1]" mode="process-group"/>

<xsl:template match="A" mode="process-group">
  <xsl:for-each select="current-group()">
    ...

> key returns a sequence of nodes you still need to use a choose (or
> apply templates) to cause any action to be taken with those nodes.