AskWOWit: Is there ANY solution for creating a keybinding that will always target the main tank's target, automatically updating for who main tank is?

I have tank targets setup as pitbull frames, but trying to click that frame isn't nearly as fast as hitting a single key on my keyboard. Is there an addon or a macro or something to handle this? I know I can do it manually, and I have in the past, but it can be a real pain to remember to edit that macro every time a join a new group.

I'm thinking maybe something like the old MisdirectHelper, where it rebuilds a macro out-of-combat to always /target the tank's target. In 5 mans this should be easy, you can just find the person with the tanking role. In raids it could pick the first person on the main tanks list.

Of course, if Blizzard would just give us unitids for the roles, that would solve everything. /target tanktarget, done.

edit: I'm already using focus for CC target, focus macros are not an option.