This may all be old school but I'm running a four box in pvp and tend to use the focus targeting to allow me to switch control quickly.

For example
I have four macro's set up.
/target Sindal
/focus

And then one for each of the other toons

Then I can duplicate all my attack macro's

/cast [target=focustarget] Fireball

Now if in pvp the main goes down I just switch the focus and keep plugging