Yes, that works if the group  memebers are explicitly granted access
to the portal but it does not appear to work when a group is used to
grant access to the portal. If you grant a group called ProfService
Reader access to the portal then setup an audience  rule that says
User is a member  of ProfService there are no members in the group
after you compile it. My real question is do I need to individually
add each of the members of the ProfService group to the portal for
the audience to work?