I get some weird problems with this XSLT. If a element has the same
attribute "enamn" like another element, it gets duplicated.
<xsl:template match="@enamn">
<xsl:for-each select="key('mykey',.)">
<xsl:copy-of select="."/>
</xsl:for-each>
</xsl:template>
key('mykey',.) selects all the elements that have a value for mykey equal to
the value of the context node. So this will do exactly what you describe:
each time you hit the value X, it will output one copy of each node whose
value is X.
I don't know what you're trying to achieve by using a key here.
Michael Kay