Robin2:
IMHO it would be quite impossible to achieve that level of real-time accuracy relying only on the "immediate" transmission of a message by an nRF24 (or other comprehensive wireless system).
Hm... For the sake of brainstorming. What other type of wireless communication method would allow for that level of real time response?
This may be impracticable but would having a wifi router on the master and two wifi modules on the slaves and using sockets (TCP) achieve a fast enough communication speed?
Or lets say having the master and multiple other masters connect to a pre existing wifi network and doing all the communication there.
I don't know, maybe introducing wifi might be a bad idea. Just a thought.