Not over a IP network (i.e. not over WiFi or Ethernet like you can do with Bluetooth proxy). If so then it will be two completly seperate Zigbee networks that have no connection to each other at the Zigbee level.
You can instead only do it over native Zigbee radio using Zigbee Router devices (also known as Zigbee repeaters/expanders), see → Zigbee networks: how to guide for avoiding interference + optimize using Zigbee Router devices (repeaters/extenders) to get a stable network with best possible range and coverage