I don't think the libraries can do this automatically, right?
However, when I connect both sketches together, it does not work.
The key condition for multiple SPI devices coexistence is met, NRF connects to pins 7 and 8 while ENC28 uses pin 53 for their SS. But I think that now I need to programmatically select which SPI device I want to talk to, do the actions needed, switch this SPI device off (setting SS high), selecting the other SPI device (SS low), work with it etc. I don't think the libraries can do this automatically, right?