I think you’re going to have to clarify what you’re asking for.  If your ceiling speakers are connected to the your receiver, then they receive their power and audio signals from the receiver.  They can’t receive power and audio signals wirelessly.  Your Connect can stream audio ‘wirelessly’ and send that audio to your receiver, which is what I assume you’re currently doing?

Currently, the in-ceiling speakers are hooked up to the Connect.

I would like to operate them as I do any other Sonos “room” but ALSO have them serve as surround sound speakers for my receiver. Note that the receiver’s speakers are not hooked up to Sonos via Connect or any other means.

So essentially I want the in-ceiling speakers to receive audio from two sources:

1. The recevier
2. the connect

Maybe there is a better way to architect this…

TIA

OK, it sounds like you actually have a Connect:amp, not a Connect.  A Connect doesn’t have an amp built it so it can’t power speakers without a 3rd party amp/receiver.  

Anyway, if I’m understanding you correctly, you want a device like this…

https://www.crutchfield.com/p_543AB32/Russound-AB-3-2-Automatic-Speaker-Selector.html?tp=2045

This will allow you have the same pair of speakers powered by two different amps without have to rearrange the wiring every time.