So I am grouping nodes by predicate on an attribute and sorted the nodes based on another attribute. I put these nodes into lines in a table. I want to have the lines in the table have alternating background colors. When I use xsl:number that returns the document order # of the node but what I want is the number of the node in the grouped & sorted order - otherwise the colors don't alternate they are just lumped together in pre-sorted/pre-grouped order.