The Roland R-07 app allows simultaneous BT start/stop and monitoring of up to 4 devices iirc.
I only own 1 so I don’t know how synchronous they would run.
BT isn't a syncing protocol, it was made for consumer electronics, so if one controller and two receivers, the start-stop will likely be off a few clicks.
Finger snap at start of recording (before the perfomance...lol) can help...