I use a combination of using party1 and the following addon (for auto following/following leader): Multiboxer

This is how I target (Using a similar approach that Vyndree posted in her hunter post):

Code:
#showtooltip
/target [target=party1target,harm,nodead]
/cast [nomod] Lightning Bolt; [mod] Chain Lightning
I bind F1-F4 with the following, setting them to the appropriate PiP window as well:

Code:
/script NewLeader("Illii")
And the following for following:

Code:
/script FollowLeader()
So, upon hitting F1-F4, I get an immediate switch of PiP, party leader, and the new alts immediately follow the new leader. So far this has proved effective for me, and I actually don't hate collection quests anymore! I can always switch to the next character when one fills up on their items

I also fixed Zanthor's Quest Broadcaster and added that into my setup for finishing touches. I'm lazy and try to maximize efficiency hehe...