nRF24L01 6TXA_1RXA network + 6TXB_1RXB network with arduino
You can use the RF24 library that you can install right away from the Arduino IDE. It provides you all you need. Just use two instances of RF24 with different CSN and CE pins assigned to get started.

RF24 radioA(7, 8); // CE, CSN
RF24 radioB(5, 6); // CE, CSN


Use the simple ping sketch as a starting point and add a second radio to it.