I have a fleet of balenaSound devices and when I play music it plays music on all of them (multi-room). But I was wondering: is there a way to choose which devices in the fleet play music, like for instance: the Sonos app where you can group specific devices. So is there an app? Thanks for any help given! 
Hi
We don’t have a phone app for this as such, though I’ll pass on the feedback to the team!
What you can do is disable multiroom on a device by setting a variable - see instructions here. You can do this using the balena-cli as well as the dashboard. See how to do it using the CLI here.
If you can put this in a script, and call this script whenever you want to disable certain devices, I think you will get the desired effect. This is not exactly the groups functionality, but it gets pretty close to what you describe