If you know how to do it is simple. But nor Loxone, nor the loxwiki provided an example. That is why I share it here

The RPI4 Loxberry has a Zigbee antenna connected and MQTT2Zigbee installed.

Two output commands are implemented in a virtual output:

- Dimmer (Helderheid)  : zigbee2mqtt/dimmerbank/set {"brightness": <v>}

- On/Off (Schakelaar)    : zigbee2mqtt/dimmerbank/set {"state": "ON"}    and   zigbee2mqtt/dimmerbank/set {"state": "OFF"}

 Two MQTT input functions are implemented in a virtual input:

- Brightness:      MQTT:\izigbee2mqtt/dimmerbank/brightness=\i\v

- Link quality:    MQTT:\izigbee2mqtt/dimmerbank/linkquality=\i\v

Below the definition of the Virtual output connecting to Loxberry MQTT2Zigbee