htaccess Elite

Hello friends,
I damaged my brain with thinking about a solution for my problem. Maybe some of you gurus have a solution for me?!:

I have three users (user1, user2, user3) - all users have to log in - at least I would like to accomplish this. And there is a second task and this gives me headaches...user2 and user3 can just log in from the ip 1.2.3.4 where user1 can login whereever he wants to.

Did I explain my problem properly? Maybe someone of you specialists may help me, please?

Thank you very much in advance, best regards from Austria
burnhard1979