No guarantees, but here’s where I’d start. I don’t think C4 differentiates between different types of Sonos devices. So in Composer, don’t bind the Port to the AVR. Set your audio endpoint 1 & audio volume 1 as the Port. (If you have other audio sources in that zone, you’ll probably have to make the Port its own room). Then in programming, when room selected audio device changes, if room selected audio device is Sonos Port, turn on AVR, delay a second, set AVR input to whatever input you’re using for the port.