[xsl] for-each-group group-by

[Craig Sampson <Craig.Sampson@xxxxxxx>]

Hello,
  I am creating an index of paper titles using xsl:for-each-group to select
and group by the titles of the papers alphabetically using the first character
of the title.

Eg:
  <xsl:for-each-group select="//section"
group-by="upper-case(substring(normalize-space(paperTitle),1,1))">
    <xsl:sort select="current-grouping-key()"/>
   . . .

  Some of the paper titles start with double left hand quotes. Others start
with a numeral. In those cases I want the group-by to use the first alpha
character in the title string. I could do this if regular expressions were
allowed in the group-by attribute, but they're not.

  Can anyone suggest how to make this work?

Thanks,
  Craig