Well, knowing ip's isnt always important for router communication. Having the server, router/switch/bridge hostname is the best way to go. Using Telnet, you can access the router and server options successfully(if you have login permissions), and from there you could use the file sharing properties to the specific computers. Now what you haven't explained is what exactly you want to be able to do with computer in other rooms.........its kinda limited to what you can do remotely.