6th axis for ATC

Hello, I use QtDragon with 5 axes (X, Y, Z, B, C) and have expanded and flashed my Mesa 7i76EU with a 7I85s. The additional 4 axes are also displayed with sudo mesaflash --device 7i76eu --addr 192.168.1.121 --readhmid. As far as I know, QtDragon can only handle 5 axes. I need an additional axis for the ATC that doesn't need to be displayed in QtDragon. Can I control it via G-code, e.g., G0 W100, or if G-code isn't possible, via HAL commands?

I read that you can customize the xyzbc-trt-kins file, but I can't find it?

If I hadn't already occupied all 5 axes I wouldn't have a problem.
Is it possible that my 7i85s card can't control any motors? Does this only work with the 7i85 (without S)? I can't find a clear answer online. Thanks.

As long as the axis is only controlled by gcode (with no direct display/control from the GUI)
it should work.

You will have to do some hand editing of the hal file to add
the additional joints/axis and kinematics specifier.