223809 Redirect homepage

Dear Programmers, I had it already, but lost i n the last years with making updates. I have a member website, and I want it for some members, not all members, but only members that are in a other group then normal users to be be possible. If a username is username1 and another user is calles username2 and another user is called username3. User 1 is in group 10 and user 2 and 3 are in group 100 Now i want is that is someone is typing in: [login to view URL] that is goes to the [login to view URL] if someone is typing in: [login to view URL] it must be redirected to a profilepage, same this with username3. If a REAL subdomain exists for example : [login to view URL] then it MUST go to this subdomain Hope it is clear.