Question from an absolute Newbie

Hello Community/makers,

I’d have a question about grove or perhabs other possibilities:

As far as I found out, I need for every grove module (relay, sensor or others) always one Arduino board? Or is it for example possible, to have one Arduino-Board, that controls the modules also over the RF-Kit? So I have the sender on the arduino and on the reciever is for example the Relay. So I can send the signal to the relay and open/close it remotly?

Thanks for a fast answer.