Hi Randy,
It sounds like what you're trying to do is identify various subgroups of users on a particular application group. One way to do this (you may already know this) is to use relational segments. In order to do that, you have to define the segments, (say) segments A, B, C,... Then you effectively relate users to the application group by creating a relation (represented by a rel_id) between a user, (say) 'a' and segment A.
There are several good and detailed discussions of these concepts buried in the forums. One such thread that describes and provides sample code is the one I created awhile back located at https://openacs.org/forums/message-view?message_id=116231
Randy