The Sonos Control API documentation makes a crucial distinction: a household contains players, players belong to playback groups, and each group plays the same audio in sync. A group can contain only one player, and a player can move between groups. This is not the same as your persistent Entertainment Area cards or floor-plan locations.
For HomeControl, keep the saved area layout independent of temporary Sonos group membership. When a room should hear two different sources, the app needs separate playback groups and a clear way to show which speakers belong to each session; simply adding another source label to one group cannot make it play two independent streams.
The official docs also warn that group IDs and session IDs are ephemeral. Cache stable player identity and rediscover live groups rather than treating a group ID as a permanent room identifier. This one design rule can prevent subtle bugs after speakers are regrouped.
Additional details — https://docs.sonos.com/reference/playbacksession-createsession-groupid | Go to Source — https://docs.sonos.com/docs/control