Individual Sonos’s x Spotify Family

How are you phrasing your voice commands? I think you need to specify “play x in room y”. 

It's not possible to stop one of your children playing music on one of their siblings devices, the concept of blocking is not included. As @nik9669a mentioned it is possible to play music on a specific device as per this article: https://support.sonos.com/en-gb/article/list-of-voice-requests-for-sonos-voice-control

Alexa voice control provides more control via Alexa Groups than SVC currently.

Thank you for the replies @nik9669a and @UKMedia 

I’ve tested the following without much success:

1. Start a session via SVC on one child’s speaker. (See screenshot below)
2. While that’s playing ask another speaker to play something. “Hey Sonos, play Taylor swift in June’s Room”
3. SVC replies on the correct speaker but plays whatever is already playing on the system. In this case “Where’s the rum gone” plays on June’s Room and stops on Ewan’s Room.

Is there no way to enable concurrent streams? Specifying the room doesn’t seem to resolve the issue of taking over the playback from the other speaker.

 Unfortunately with Alexa you can’t assign different wake words to Sonos devices.  With Echo speakers there is a choice of 5 wake words.  Very handy.

I can't test here because I only have one SVC compatible speaker, but I believe your issue is here:

• The child’s Spotify account has been selected within their instance of Sonos app

I doesn't mind the instance of the Sonos App. SVC is going to play from the Default Service:

I understand you have multiple instances of Spotify as Connect Services and they have different names, e.g., June's Spotify.

Try a command like this and let's us know: “Play Taylor Swift on June's Spotify in June's room”.

Can you confirm that you have added each of the Spotify accounts as per https://support.sonos.com/en-gb/article/use-multiple-accounts-for-the-same-content-service

Did you test if it worked so that you separated the speakers to their own Sonos systems? That might not always be ideal* but might solve the issue if it doesn’t matter that they couldn’t control the Living Room either or your controller Sonos app didn’t see their speakers in the same system as the Living Room. 

1. Reset one of the iPad Sonos apps and add the child’s speaker with that as a new system. If you used your account on their iPad then I’m not sure if there’s a restriction on Sonos Voice Control (SVC) of concurrent use. If you created a new Sonos account for them and used that then they definitely should be separate. SVC and Spotify should then work independently (the preferred service would then be the child’s account).

*) The downside would be that your controller Sonos app wouldn’t see their speakers as I think it is still so that a speaker can belong to only one Sonos account/system. You’d need to switch between the systems in your Sonos app if you wanted to control their speakers with your Sonos app. The Sonos app should remember that last system it connected to.

Given the issues some users have with the latest Sonos app, trying that might be risky but if you are willing to risk the speakers not immediately being set up, disappearing or somehow disrupting your working system etc. then that might be one way to try.

With the latest Sonos app switching between systems may or may not yet work as seamlessly as it used to, if I remember right, or maybe it’s been fixed already: https://support.sonos.com/en/article/connect-to-multiple-sonos-systems 

If you search with two systems on one Wifi you should get some results like this:

https://en.community.sonos.com/controllers-and-music-services-228995/how-do-i-set-up-two-systems-on-one-wifi-6884233#:~:text=Use%20a%20different%20mobile%20controller,using%20each%20different%20controller%20device.

With the current setup: in the childs’ Sonos app, what does the Default Service under Sonos Voice Control show? Is it different in each iPad or is it possibly showing the same account? That still wouldn’t explain why it didn’t start playing Taylor Swift but moved the Rum to the other room. 

   For me with SVC it is so that if music is playing in Kitchen, and in the Kitchen speaker I say “play in the living room”, the Kitchen music would switch to living room -- and not start playing the living room queue that I intended. I’ve solved this by saying “hey sonos stop” (stops Kitchen), “hey sonos play in the living room” (starts Living room). If I then wanted to also play the Kitchen, I’d say “hey sonos play” (starts Kitchen which has separate music). Your Taylor Swift example doesn’t explain why the Rum moved there and Taylor Swift didn’t start, though.

This was slightly similar question, on using different voices on same system. There is some discussion about Alexa voice as well: