If you are using the tradfi routers (the ones that look like a smartphone charger) then you just need to pair it with the zigbee network 
that’s all, because that router doesn’t do anything else. I wouldn’t even bother to sync it with openHAB because it has no other function:
It’s a charger and broadcasts the zigbee network.
Then you place it in between the temperature sensors and the coordinator (the zigbee stick which I use is the sonoff one with the metal casing and an upgraded antenna) and the sensors will eventually connect to it by themselves.
