I am in same situation. I owned the house and it has ceiling speakers with proficient audio system (ss4p). But I could not fi
Hard to answer an incomplete question. If you have the ceiling speakers and the impedance matching speaker selector you will need a stereo amp or receiver to drive the speakers and sources to listen to.
If you want a more flexible system you can use 2-4 Sonos Amps without the switch box and be able to operate each room or zone separately with the Sonos app.