Ive checked the RFM69 and ive decided that iam not going to try it But instead, if i read it correctly i can use an Arduino + (official) Ethernet shield as a gateway. Domoticz supports multiple gateways, so i should be able to place an Ethernet shield on each floor and use the NRF's to each gateway ill how that works out BTW: this is an W5100 right? https://www.arduino.cc/en/Main/ArduinoEthernetShield