Bug?

Today I have tried to run 3 Chars on my Main PC and 3 Chars on my Laptop. So my problem now is to assign groups to my chars correctly so my follow setup will work. But now I saw that I can only assign a Keymap to a Character Slot 1, 2, 3, 4, or 5. But where is number 6? I have 2 Charsets with 3 slots each.

Edit:
After a while I understud the way things work. But I think it is a complicated way. As I wrote in an other post IS Boxer should go an other way which is simpler to understand and it would it make easier to setup multible configurations. Right now I can't run different charsets with two PC in one configuration because I can't assign a mapped key to a slot on the second PC independent of a character.