‘Living Room’ and ‘Living Room 2’ are not different systems, they are the (room) names of each Sonos device added to your Sonos system. The standalone device names need to be different as they are classed as two different rooms/devices. They only usually get the same room name when devices are ‘bonded’ together (as part of a Home Theatre setup) or ‘paired’ together (to make a stereo pair of ‘like’ speakers).

There are certain restrictions when it comes to ‘bonding’ or ‘pairing’ but it’s not clear what your ‘Living Room’ Sonos device is, or what you’re trying to achieve here? You can of course go onto ‘group/ungroup’ your ‘Living Room’ and ‘Living Room 2’ devices as explained in the following Sonos support document…

https://support.sonos.com/en-us/article/group-and-ungroup-rooms

Thats if that was what you were trying to achieve?

You can also go onto rename your Sonos ‘rooms’ too in the Sonos App, goto ‘Settings/System/sExisting Room]’ and select the name underneath the Room section heading to change its name. It’s best to keep the device room names unique.

Hope that assists.

Thanks for the reply. What you said makes sense. Simply put, what I’m trying to achieve is this: I’m trying to take the One SL and add it to the Living Room group, which is already set up as a surround system, consisting of 2 SLs, a sub, and a playbar. I was hoping that I wouldn’t have to ungroup everything and start over just to add one more SL to the mix. 

Just group ‘Living Room 2’ to your ‘Living Room’ as explained in this LINK. Note you cannot ‘bond’ a further One SL to the Playbar because you have two rear left/right surrounds (channels) already and the Playbar itself has the front left/right/center (channels) built-in.

So that’s a total of 5 channels, plus your Sub, making it a 5.1 Home Theatre setup.. you can’t ’bond’ a 6th channel, but you can ‘group’ the new speaker to your Playbar room. 

A couple of things to note… for Music audio, via the Sonos App etc; the ‘grouped’ devices will all play in perfect sync, but for TV audio you will likely notice an approx. ~75ms audio delay to the grouped speaker ‘Living Room 2’, this is by design and is to cope with grouping issues over a wired, or wireless, Home network. That latency ‘may’ sometimes cause an echo effect when the devices are located in the same room.

There is an option/feature in the Sonos App to help bring TV audio over ‘grouped’ rooms into sync called ‘TV Dialog Sync’ - read more about that in the below link, but note that syncing the grouped room audio, may result in lip-sync issues with the video on screen, but some users, particularly when playing stereo audio, may not notice the slight delay - but it can depend on network conditions, listening distance from the speakers etc. Anyhow see this link…

https://support.sonos.com/en-us/article/tv-audio-and-video-are-out-of-sync