I’m not near my Sonos system to check, but if you’ve tried the ‘add a service’ and it isn’t there, you probably should send them an email, pointing them to the Sonos partners page, and suggest to them that they join the Sonos ecosystem. 

You didn’t mention what device you’re using to control your Sonos system with, but if it is an Apple device, you should be able to use AirPlay 2 to send the data to the Sonos. Unfortunately, Google has chosen not to implement Chromecast for Android devices, you may be stuck if you’re using an Android phone. 

And there is sometimes the possibility, depending on our setup, of sending the data through the TV itself, of course the Ray would then play what the TV sends to it.