Hi, lmr1121 and welcome to the forum.
This would be a great question for New to Using the OBi / VoIP forum. In fact, this question was asked and answered many times.
In short, no - you can only hook up one physical phone to OBi100 or OBi110. Both OBi202 and a "small router" would work. Is there a router in current configuration? If yes, than you probably meant "a small switch".