I get lazy that way, so I make a relatively all encompassing dps macro for all my toons and put it in slot one. Then I keybind center mouse button to slot one. Sit back and click click click ftw. This won't do instances for you, but sure is nice for leveling that 4th (or whatever) team. Mine is something like:

/assist focus

/cast skinning [target=focustarget]

/petattack

/!shoot

I just stick that on whatever, melees will attack, pets will attack, wanders will shoot. This is incredibly crude and I'm sure one of the whizzes here could improve it significantly.