what do you mean by 'exact same thing'? you could be confused as to what is possible within wow. if you think you'd like to move and they would all move the same way, to the same place, that just won't work since they all have different positions and direction vectors.

you need to have your 'alts' (an alt == the ones you are not actively using) all /follow your 'main' (your main == the one you are actively on)

once they are all following, you must make sure to put your movement keys on the do-not-pass list, otherwise the movement key will break follow on your alts.

with that done, you need to synchronize targeting. you can do this numerous ways, the simplest is doing a basic /assist macro to assist your main. this is not the optimum configuration, but it does work and is suitable to about 10-20 (although i have been told its been used all the way to 80). i generally recommend doing it this way to start, so you get use to multiboxing and aren't tripping over issues with macros. once the multiboxing stuff is second nature, then you'd be ready for a better/faster/less-keys-to-press targeting mechanism