Grouping upon various attribute values

Hi all,

I have a little problem, which gives me a bit headache at the moment.
Maybe you could help me solve it :

Here the given XML :

		<produktenZumAnalysieren>
			<gesamtMenge>
				<filter aufAttribut="Name_Stat"
typ="diskret" wertStruktur="baum" wert="BP"/>
				<filter aufAttribut="FrankaturArt"
typ="diskret" wertStruktur="genau" wert="PP"/>
			</gesamtMenge>
		</produktenZumAnalysieren>
		<produktenZumAnalysieren>
			<gesamtMenge>
				<filter aufAttribut="Name_Stat"
typ="diskret" wertStruktur="baum" wert="BP"/>
				<filter aufAttribut="FrankaturArt"
typ="diskret" wertStruktur="genau" wert="PP"/>
			</gesamtMenge>
		</produktenZumAnalysieren>
		<produktenZumAnalysieren>
			<gesamtMenge>
				<filter aufAttribut="Name_Stat"
typ="diskret" wertStruktur="baum" wert="BP"/>
				<filter aufAttribut="Gewicht"
typ="interval" wert_Ab="1" wert_Bis="100"/>  //<- Careful here, there is
a new set of attributes
			</gesamtMenge>
	</produktenZumAnalysieren>

As you can see, there are three "gesamtMenge" elements, each in its own
"ProduktZumAnalysieren" element.

Now, I would like to apply a for-each-group loop on them :

	<xsl:for-each-group select="produktenZumAnalysieren"
group-by="gesamtMenge/filter/@* (KICKME HERE)">

That is, the grouping key isn't doing what I expect: I need to have all
attributes taken in consideration for grouping the required elements. In
this example, I should have two distinctive groups

Any help would be really greatfull ;-)

Cheers

Lawrence Michel, Bern, Switzerland