Help with Groups Name

[Al]

I am trying to allow the user to see certain things on a
form based on which group is he a member of, not based on
Currentuser(). I am not sure how to do that? Does anyone
have a routine that can check for the goup name so that I
can determine whether the user can see or not see some of
the info on the form based on the group the user belongs
to.
thanks
Al