I'm not really sure what you mean that isn't the point. You said GSX doesn't let you load containers and pallets at the same time. I told you to check the GSX aircraft profile because you can select them there. At least with P3D, you could select multiple items, in which case, you could select both containers and pallets, and that would, in fact, solve your problem. I'm not sure if MSFS allows you to select multiple items simultaneously because I don't use MSFS, so I can't check and confirm, although I don't have any reason to believe it wouldn't do this. If the pallets are too big, of course that would be a different issue altogether.