Not sure I understand exactly what you’re asking.
So, Sonos ‘rooms’ can always be grouped to play the same input in the controller. The only caveat is, any room that is grouped with a ‘home theater’ room (read: using the digital input from the TV) will be slightly delayed, by around 75 ms. The only time you’d likely notice this is if you could hear both ‘rooms’ at the same time. I suspect if you’re in the pool, you won’t notice.
I used to do this when I had a separate kitchen, the only time I noticed was standing in the doorway, and could hear both ‘rooms’ at the same time. Now that I have an open floor plan, I just turn up my Arc slightly.
If you have the Sonos/Sonance speakers six is an option, adding a speaker selector switch would allow disabling any unwanted speakers.
If you have other speakers then you would need an impedance matching speaker selector to keep the load presented to the amp at 4 Ohms.
@Stam I know six Sonance speakers can work with an Amp. Will they also work with a (much less powerful) Connect Amp?
I believe they will, they will play less loudly though.
Stuck on a small screen tonight so finding the Connect Amp / Architectural speaker specs is difficult.
If you can't connect six directly then the impedance matching speaker selector would be needed again.
Just thought of it …. Move 2 or Era 100 smart speakers would just do it. They would allow to create a pool zone and would be waterproof.