Multiple M1TWS's in outbuildings

[Ira]

I want to put a few M1TWS's (speaker/mic combo) in my shop which is about 200' wiring distance from my M1G can (which also contains the M1TWA). I have a cat5e cable running between the two that is used for phone (two phone lines/numbers). Can I steal the other four conductors and use them to connect three M1TWS's in my shop? Is the cat5e "heavy" enough (24ga.) for this use over this distance?

Thanks,
Ira