Motor mixer for rare shape multicopter

in the DJI A2 there is a motor mixer for rare shapes. It can mix the settings for pitch roll and yaw. We use it for a rare shape and works fine. Now we are moving to the PX4 because of much more open PID settings. However we do not have such motor mixing scheme that is normally very easy to use. Can one of you let us know if such matrix exists for PX4? I hope my upload is visible to you so you see our issues.

Best regards Winfried

you have to create custom mixing file, more details