Best answer by Keith N
In a multi-household situation, it is important to understand that the Sonos skill in the Alexa app is tied to the Sonos ID. This means, that when you tell Alexa to play X on Sonos, Alexa is controlling the house (Sonos System based on SonosID) it is connected to. The best way to do a multi-household set-up would be with different Amazon Accounts and Sonos ID's. This would be similar to treating each house/location as a separate "household". When going into the Sonos app you are going through the local network, this is why you can control playback normally from within the app.