Hiding the Domain

I have a Class C network in a university environment. Clicking on network neighborhood shows all the domains in the university. Unfortunately, this invites many attempts by students to logon to our network. Even though their success rate is 0 we still have to spend the time documenting and reporting these abuses. I have a two fold question.

1) Is there a way to hide our domain name from the network neighborhood so the students don’t know we are there. (500 points)

2) Is there a way to post a warning (when the student clicks on our domain) that shows up before the login window appears. (500 points)