Correct…you can’t be checked in to each because your MB can only attach to one resort at a time.
Now, they have a way to uncheck you as a guest, but if you are the only one on the first reservation then it is going to be an issue…
When my DS and his wife went to stay a night at VGF while the rest of us were at BRV, they had to unlink them from BRV first,, when they came back, they were checked back in…but the rest of us never left.
What I would do is make your name on the one you booked at Poly your middle name and don’t link it to
MDE…and then just get a key card to open the room.
That should allow it to work..but not 100% sure. We will double book a night when we split stay so two rooms for one night, but we don’t check in to the second resort until we left the first one, so don’t have the issue. We just do it to have a room from 11 to 4.