Use of HOTAS in mission planner

I’m trying to bind functions to my Thrustmaster Warthog HOTAS but Mission planner will only allow a connection to a single USB device.

Has anyone else dealt with this? I’ve found very little information online

Mission Planner only supports one device at a time.
But you can combine any number of physical devices into one virtual one with Joystick gremlin and vJoy.