Raspberry Pi NRF24L01+ + MQTT + MQTT Gateway

[siod]

Hi guys,

I succesfully build a MySensors MQTT Gateway and a MQTT Client using arduino nanos. Now I installed Mosquitto on my Raspberry Pi where also Openhab is hosted. I´ve read a lot in the forums and also google, but I don´t get Mosquitto to work proper:

First of all I need to now if I can connect the MQTT Gateway to the Raspberry somehow, because the Raspberry Pi does not have an NRF24L01+ Module and so it cannot get any messages. The Raspberry is only connected to my ethernet, just like the MQTT gateway. I´ve read sth. about "bridging" but I still don´t understand what I have to do and if it is the right way.
Or do I have to add a NRF24L01+ module to the raspberry Pi as well?

Please help me here because I´m stuck for weeks now! Thank you!!