Setting up an ISOLATED workgroup??

I have a LAN with wireless internet access (Cisco Systems
350 Series) on IBM's, all running Win98. I have a room
that I want to setup a workgroup in, so that they would be
isolated from the rest of the IBM's, so I can network a
printer strickly for that one room.

Could anyone tell me the steps I take to put them on a
different subnet (if that is what's needed to be done) and
at the same time NOT interfere with their internet
connection. ALL useful info accepted and more than
welcome! THANX N ADVANCE The Rookie/Wayne B.