Plenty of properties run both — a few private doubles alongside two dorms — and they should not need two systems or two boards to do it.
A single switch on the room type decides whether it sells whole rooms or beds. The board keeps the two as separate groupings so a property with no dorms renders exactly as it always did, and a dorm renders as an occupancy against its physical room.
That switch is immutable once the type has rooms, and the reason is worth knowing. Flipping a type from rooms to beds leaves every existing room in a configuration the guard would have refused at creation, and flipping it back leaves beds grouped into units that no longer mean anything while occupancy jumps from one to whatever the form supplied — re-pricing every open reservation on the type.
Neither direction errors at the moment it happens, which is precisely why it is refused. A property restructuring creates a new type and moves rooms across deliberately, which is free while the type is empty.