Delta_G:
SPI is meant to be shared. They only need different CS lines. There shouldn't be any need to much around with software SPI for that.
what do I need to make to use nrf24 and usb host shield to work together at the same time ? I really don't know how to solve this problem, nothing on internet about it unfortunately 
From the readings, what I understand is "nrf24 and usb shield are using the pin 10 as SS ( slave select )"; so how can I change and assign that pin 10 to another pin which will make these two modules to work together ? thank you.