Hiding addresses in Exchange 5.5

We have 3 email sections under email groups. We’d like all of the addresses in one of these groups to be invisible to the other two groups. I found where you can hide an individual email address in the advanced tab, however when we selected this the address disappeared even from the server so that we can’t administrate it. Is there some way to set it so that the administrators can see the address through exchange 5.5 only? Or to regulate who can/can’t see an address or group listing? THanks for your help.