If you want to primarily use Home Assistant’s ZHA integration as your Zigbee gateway implementation then the best workaround, for now, is probably just to buy another Zigbee Coordinator USB adapter (preferably one based on Texas Instruments CC2652P such as example the Sonoff ZBDongle-P model from ITead), then in parallel install and use Zigbee2MQTT (via MQTT in Home Assistant) for any ZGP (Zigbee Green Power) devices you got since it supports Zigbee Green Power. See → Home Assistant addon | Zigbee2MQTT
Note that while you can use Home Assistant’s ZHA integration and Zigbee2MQTT at the same time but they will have separate Zigbee networks that will no knowledge of each other, so if you primarily use Home Assistant’s ZHA integration you will still also have to add a few Zigbee Router devices to Zigbee2MQTT to get good range and coverage for the Zigbee Green Power devices. Zigbee2MQTT
can be installed as an addon or stand-alone on a separate computer, read → https://community.home-assistant.io/t/guide-for-zigbee-interference-avoidance-and-network-range-coverage-optimization/515752/