NRF24L01 Direct Communication Library Logics
Both of the Libraries you mentioned are well written. I've used both, but decided to write my own based those libraries. For me, the network libraries were written for their project and didn't really fit my needs. So I decided to write my own. I combed the internet for a bare bones NRF24 Library and found this one. This was my starting point. It didn't need the Arduino Core Library and handled all the SPI functions. Then I read the NRF24L01 datasheet several times, then read it again. 

With that said, you can broadcast up to 6 radios at a time. Per the datasheet, the receiver knows which radio sent the packet. The STATUS register (0x07), should tell you who sent the packet:



I was unable to get this working (I am still working on it), so for now, I send my packet as a struct:

typedef struct  {

uint8_t id;
uint32_t data;

}
Packet;

Packet pck;
pck.id = 2; // id of my second radio


Keep in mind when you program your Arduino as the receiver, you have to tell it who it will be receiving from. The transmitter and receiver have to be on the same RF channel, speed and same pipe. To choose who receives the packet may not work the way you think, but as I mentioned you can program the receiver to know who the transmitter was and code around it.

I would suggest you dig into the datasheet.