What is the udp mavlink port for the vehicle?

I am launching An iris and a plane in same gazebo instance with 2 PX4 Instances,

PX4_UXRCE_DDS_NS=plane PX4_SIM_MODEL=gazebo`-classic_plane_lidar $PX4_BUILD_PATH/bin/px4 -i 1`
PX4_UXRCE_DDS_NS=iris PX4_SIM_MODEL=gazebo-classic_iris $PX4_BUILD_PATH/bin/px4

And the link between ros and px4:

MicroXRCEAgent udp4 -p 8888

I tested offboard mode and everything looks fine, But the topics in off-board mode doesn’t support some of the mavlink messages like SET_POSITION_TARGET_LOCAL_NED

So I am trying to use direct UDP connection to connect to mavlink, but I am not able to find the port, connecting port 14445 randomly connects to both vehicle, How can I add a extra dedicated port for custom mavlink control.

Thank you & Regards

Why do you need MAVLink? you have a way faster interface, look up the messages supported here, it’s a completely different API

This example from our docs will help you understand what you need to do ROS 2 Offboard Control Example | PX4 Guide (main)

The publish trajectory function is not working for fixed wing, hence I am trying to send direct mavlink command.