it is possible to control multiple closely located tiny houses individually through a single Home Assistant setup. For instance, one user could turn on the lights for house number 1, while another user could shut down the electrical system for house number 3. I appreciate your inquiry, and thank you for sharing.
As explored further in a previous post, each HASS instance only has Admin and User. All users have access to just about everything, with only the ability to limit which dashboards are visible.
The HASS phone app supports multiple HASS servers (Multi-Server Support), with the ability to switch between them using a three-finger swipe.
For the example, you could run three HASS instances, and only give access to users by server. A user with multiple server access, would need to use a phone app and manually switch between them.
This is rather clumsy, although it would be possible for one HASS instance to communicate with the others via RPC, webhook, or MQTT (e.g. one trigger fires automations across all servers).
If this helps, 
this post!