Simple one for one swap of items in a slot within two inventories

Especially \an issue when dealing with full inventories I'd like to have the ability to simply take an item or stack of items and simply drag and drop to an already occupied slot in another inventory. In this case the item whose place i was taking with the drag/drop stack would find itself in the starting inventory. As of now if I and my follower have full inventories but I wish to have them carry something in my inventory due to weight etc I need to (1) drop something else in my inventory (item A), (2) drag item(s) B from their inventory into my inventory hoping they won't pick up Item A; (3) Drag item C from my inventory to theirs. (4) And give up on Item A. I am asking to be able to drag (1) Item B from their inventory to the Item C spot in my inventory and (2) drop Item B there so then Item C appears in the former Item B slot in their inventory