I believe you can set more into your focus macro



/focus [target=party1,nodead][target=party2,nodead] so on and so on... this way it checks to see if there is a party1, then checks to make sure its not dead. If they are dead it moves to the next one to make your focus and so on. however that will not change your screen for you. Like elsegundo asked how do you currently change your leader currently?