Not easily, and certainly not with any of the equipment you currently own. You’d need to have a Sonos device with an analog line out, such as the Sonos Port, which you could then connect a Bluetooth broadcast device to, and send that signal to your Bluetooth speaker. It’s possible that their might be some latency in that Bluetooth signal, or not, it would depend on the capability of the transmitter you attach to the Sonos. 

Note that the Sonos Move, while in Bluetooth mode, is merely a Bluetooth speaker, and is not part of the Sonos network. It does not share its signal with other Sonos devices while in that mode. 

Thanks Airgetlam. I had a sneaky feeling that it would not be a simple “fix” , to play my Bluetooth speaker through my Sonos system ………… and I’m pretty sure , Sonos would not make it easy for people to use speakers other than their own !!!!

Thanks for the interesting fact about the Sonos Move as I had mistakenly thought that I could play my music to this speaker using bluetooth ( if i bought one ) from my phone and it WOULD play in all of my other speakers at the same time , but obviously not from what you have said. 

If you ever hear of a simpler solution to play 3rd party bluetooth speakers from a sonos system, I would really appreciate it if you could let me know. Thanks. Stay safe and cheers Jimmy