Ok I think I am following.  I currently have two listing linked on the calendars.  One with hot tub on the room the other with it not included.
 
So I guess if I created the 3rd listing with Bedroom 2 and linked it to the others that might work.  But i would probably have to assume the 3rd listing takes the 1st room the 2nd room and the hotub as one big package and would block the calendar.  
 
I guess I might be able to do a 4th without getting too cleaver and linking it the the 2nd listing without the hot tub. 
 
I will play; thanks!!!