If you are going to have 5 blinds why not just use a byte or bit in the payload to correspond to each blind? As others have said, broadcast to node 255 so they all receive the packet and then within the packet if I find 01000 000 in a byte and that 1 is my bit, then I change from open/close. If I find a 0, I do nothing. Or the 0s and 1s could be closed and open and I make my state whatever the flag calls for. Just don't request an ack when your gateway broadcasts to node 255 so you don't have to handle collisions.
EDIT: Or I could have said exactly what Tom suggested, oops! Flags is the way to go here.