You’d want to set up each Amp as its own Sonos ‘room’ and then group them together for playback. The Sonos devices have no knowledge of physical space.
You definitely can do this, but...each Sonos amp can be connected to 2 pair of 8 ohm speakers, and from my experience, handles this just fine. So that covers 4 of your 6 speakers. You can also setup a 2nd amp bonded to the first to cover surround sound speakers. Probably not what you want if playing TV audio, but for music sources, you can configure ‘full’ stereo, meaning the surround speakers play stereo just like the ‘front’ speakers do. So now you have 6 (potentially speakers playing off 2 amps bonded together for a single Sonos room.
Or, if you get the Sonance ceiling speaker packaged offered on this site, they are specially engineered to allow connecting 3 pair to a single Sonos amp. I don’t think these speakers are rated for outdoor use though. Or, you could get a 3rd party impedance matching speaker switch off of a single Sonos speaker.
So yes, this can definitely be done, and there are lots of ways to accomplish it.
You’d want to set up each Amp as its own Sonos ‘room’ and then group them together for playback. The Sonos devices have no knowledge of physical space.
I had a tech come and install 6 speakers to one amp, utilizing impedance matching volume controls.