Even though its cloning you can still do clever things akin to separately controlling each character.

You simply use hotkeys that do something on one character and nothing on another character. For instance maybe your priest will cast group heal when you press Shift+F, none of your other characters will have a skill bound to that key.

At this point you can start to do clever things like grouping skills you think would be good to cast at the same time. Maybe you have a priest and a warlock, you can bind the 1 key to cast curse of agony on the warlock and also cast sw on the priest. You can group up nukes and dots or other spells that have similar functions to the same hot key.

Think about all of your characters as 1 character with the abilities of all 5, you can do it, but you just need tons of hot keys.