@Magnus102
You can create a listing for the house, and then link the room listings within the house listing using the “Airbnb Calendar Linking” option under the house calendar/Settings/Availability. This will set up the house as a “parent” of the rooms.
Alternatively, you can just set up a new listing for the house, with no availability, and then unblock August. Then, in the rooms, block August.
The former has the advantage that you can have a combination of room bookings and house bookings. The Airbnb software will sync them so that booked dates in one will render them unavailable in the other.