You need to explain what you want to achieve. There is a lot of confusion about pipes and how they should be used. You may not need to use multiple pipes.
The simplest solution is for the master to have a list of all the addresses of the different slaves and call each of them in turn. That way there is no risk of a data collision.
However if you want a previously unknown nRF24 to make a call to the master it will need to know the master’s address. There will be a risk that two nRF24s
broadcast transmit at the same time and cause garbage.
In either case the ackPayload feature provides a very simple way to implement 2-way communications.
Have a look at this Simple nRF24L01+ Tutorial