In a multiple family household, it’s possible for each member of the family to have their own own login to a particular service. However, you can’t associate that service to a particular Sonos within the house.
I know in our household, I’ve setup the accounts on my controller, and now Apple Music is convinced that I’m really into Broadway showtunes, “Julie and the Phantoms”, and lullaby versions of popular songs. These are being played by my kid’s in their rooms, and they never remember to select their service/account to play from (especially because most of the time they are just telling Alexa to play something, so it just goes against the main account).
Allow for a service/account to be associated to a particular player in the house. For example, if Amy had Sonos in her room, then we want to say always play Apple Music (or Spotify) on Amy’s Sonos from Amy’s accounts.