Remote light switch

I’m looking for some advice here. I’m new to the wireless world but it seems to fit this. I’ve looked at the Xbee products and think they will fit just need some direction on how to do this.

We have a Electric gate to come into our 2 ware houses wired on separate meters. I would like to wirelessly transmit a signal from the gate to the warehouse to turn a light on when the gate motor is in operation. Also if possible I see these transmit and receive I would like to put a button in each warehouse to open the gate. Right now we have universal garage remotes.

Any ideas on how to do this?