I just checked since it’s an interesting scenario.
In fact the model allows you to have an Equipment be part of another Equipment, but also in a Location.
So if you define your 2 Locations, and Shelly relay as an Equipment, and the HVAC/Light as separate equipment, and then add them to both the Shelly equipement group and the Location groups they’re in, they will appear twice in the model - you see it’s the same item because it highlights in both places:
You cannot do that from the model page but you can change the group membership from the items pages. In the case of the light you’ll end up with this:
So it has both a isPartOf relation with the Shelly relay, and a hasLocation relation to the room1 location.