Do you already have two separate SSR reservations for four nights each? I would first start there so you at least have some place on WDW to stay if you are unable to secure your desired resorts in the 7-month window. I would ensure something is different between your two SSR reservations like guest names (you can leave someone off for now) so they don't automatically get merged. It's not common, but it has happened. Once the 7-month window opens, try modifying each reservation on your own if the room is available. If not, setup an individual waitlist for BCV to replace the first SSR reservation and a second waitlist for PVB to replace the second SSR reservation.
If you have two contracts, but one membership, you only get two waitlists. Multiple contracts would remain in the same membership if they are the same UY and deeded exactly the same. Once you change deeded names or UY you create a new membership.