Config hints for providing list of groups in post-auth?

Hello list: I have a 3.0.4 machine successfully authenticating against Active Directory. For the use case I have in mind I'd like to have the Freeradius server add into post-auth something like: Group-Name:= "Domain Users", Group-Name+= "All Staff", etc. The idea here is that the NAS will be able to make its own decisions about what to grant based on group membership once radius has authenticated the user. I can parse the group list easily enough from the shell, but don't know how to get this into post-auth. Also, is Group-Name the best choice here or should I be using another attribute? Thanks greatly, Mike