Yeah, as far as I can tell, the admin is the only one who can see what groups computers are a part of, by using the ADNM console.
Sort of the same way that users don't know what OU their computer is a part of in the domain. Well, unless they know how to use gpresult that is. Actually, I don't even think that shows the group.
Anyway, back to the point, you can only see via the ADNM console.