I have three groups of users such as Users1, Users2, and Users 3. I want to restrict who can IM and see the presence status of those user groups. Users1 should see everyone. Users2 should only see other people that are members of Users2 and Users 3 should only see members of users 3. Is it possible to restrict this using CUPC and CUPS version 7.x? Does the subscribe CSS and presence group restrict this ability?