Not sure I'm understanding pipes for NRF24
I don't see any reason for doing this. 

Multiple devices sending data at the same time will cause collisions irrespective of the pipe-nr they are using. 

Pipe is also a not very accurate name for what it actually is. It's just a number, that the receiving NRF can check, to see if the packet that was received was intended for it. Kind of like a MAC address on a network.

You can have two unique reading pipes. Then there are 4 more pipes you can use, that are identical to the second pipe, except for the last byte.

The first pipe is used to specify the pipe you are sending through. So if you send to different pipes, this pipe isn't ideal for listening, as you'd have to change it back every time you send a packet. Possibly loosing a packet that was send in between.

If you want more information, i'd suggest reading the datasheet, and read the documentation of one of the libraries. I personally checked the sourcecode of the library a lot while at the same time referencing the datasheet, to really understand what it's doing.