I just pause a lot and mostly I only need the potions for 1 char since the enemies mostly attack only 1 of my chars.
what you also can do is hotkey the potions for 1 character end leave the 'menu' for the other one open <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" />
besides, as soon as you start needing the medium potions you migth wanna "un-hotkey" the minor potions <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" />