Single Remote Modem with multi pnt dvcs

Do you know of any modems that you can dial into, and select different diveces you can talk to at a remote site? My delema is that I have a Microwave site on a mountain top, and I have several different pieces of equipment that I would like to to talk to through one dial up modem and then be able to select which device I would like to talk to and use only one dial line. Do you know of any products in the market that can do this? Thanks Don Purinton, e-mail drpurin@the-onramp.net