13. The method of claim 12 , wherein said forming a relational table comprises forming a many-to-many transfer file indicative of relationships between said instances of said at least one predecessor group and said instances of said first one of said plurality of descendant groups.
14. The method of claim 13 , wherein said forming a many-to-many transfer file comprises forming a many-to-many forward transfer file indicative of relationships from said instances of said at least one predecessor group to said instances of said first one of said plurality of descendant groups.