I am looking for an easy way to block inviting users to groups via email (SMTP). Maybe it exist someplace and I am simply overlooking it for some reason. The problem is that I work for a very large company in which only a small division has purchased SBS. We would like to use SBS only in our division and I am able to control access via AD however some of our users have been sending invites to coworkers in other divisions which we would rather not give access too at this time. Its a little awkward at the moment explaining to these people why they cant logon and its creating a bit of a mess for our admins. Is there a way that I can restrict the invite to groups feature only to the registered users roster? This would save us all a lot of headaches.