[Norfleet]

You can ungroup(and regroup) the commanders by individually removing(or adding) them from the group, by holding the CRTL key as you select or unselect them. Sometimes, for various unknown reasons, additions or subtractions fail to take effect and be remembered. Try to select the group again to make sure the added or subtracted commanders are no longer part of a group.

Alternatively, to vaporize any and all group associations for all commanders in the province, push "a" twice. The first time will select all commanders into a giant supergroup, the second time will erase that group. The end result is that all group associations are destroyed.