(sorry, but) you've simply got to be kidding, yes???
IF you change that way, you choose the individual character, and while yes, you can drink a potion, you are then left with having to click a third key to have the 'group' again.
in a heated battle, there is not enough time to click twice , let alone three different keys.
so five(!!!!!!) keys to have both drink a potion??????? that's simply ridiculous.
obviously you play with the spacebar (pause) and/or on easy difficulty.
and btw, there is indeed a way to have almost all your keys be hotkeys, not just the 'F' keys.
besides, potions are not the only problem...