Non-gps tracking for several zones

I’ve been trying to figure this out, but to no avail…

I have two “homes”: Home and Cabin, each with its own Home Assistant instance. The Home HA gets information from the Cabin HA using Remote Home-Assistant.

In the Home HA I’ve set up the Cabin zone, and the HA Companion app correctly reports my presence at Home or at Cabin in the Home HA. Additionally, I have set up Bluetooth and IP device trackers both in the Home HA and in the Cabin HA. These device trackers correctly report home and not_home in each HA instance (Home or Cabin), depending on where I am.

Not yet solved challenge: For each person entity, I would like - based on the Bluetooth and IP device trackers, only - to determine (in my Home HA instance) whether I am (and other family members are) at home, Cabin or not_home. Using the HA Companion app device tracker, this is trivial, but I would like not to have to depend on the HA Companion app (not all family members have it installed on their cell phones).

So, in my Home HA instance, I would like, based on the IP/Bluetooth device_tracker from the Cabin HA instance, to set, for example, person.wife to Cabin when device_tracker.cabin_ip_wife reports home.

I know I can do this by synthesizing a gps device tracker by using device_tracker.see and setting Cabin gps coordinates in the Cabin HA instance whenever the wife is home at the Cabin, but what would I do with the synthesized device tracker when she’s not_home at the Cabin (can I set it to unkown in some way)?

Or can I go about this in a different way, perhaps something similar to device_tracker.see for person entities?

Any ideas?