local radio(FM)

I am making a wireless local radio that the system is FM and mono ,not stereo.There is 100 receivers and 2 transmitter in the zoon.I want to turn on and off each receiver from the center(transmitter).how can I do this?I mean which IC or circuit should I use to encode/decode.because I need to use a decoder in my receiver between FM receiver and amplifire and an encoder in my transmitter.