Do the following:

1: Make the following macro on all your clones, and put it on a hotkey that's the same for all of them (I am using a follow x macro rather than a focus macro)

/follow Party1
/assist Party1

This macro will do 2 things.. Firstly, it will tell all your clones to follow the character who did the initial invite of the party (Automatically party1, but if you change leader, that character then becomes party1)
The 2nd line of the macro will make your clones target the same target as your leader, allowing you to make your next move an attack.

2: If you're using keyclone, set it up to "do-not-pass" the movement keys WSAD, if you're using other programs, do the same. (For Autohotkey, delete or put on hold, the lines in the script that pass these keys.)

3: Find a hotkey that you don't use a lot, but is still within acceptable reach of your movement fingers. Personally I prefer "1", but that's up to you. (I'll use 1 in the rest of my explanation, for simplicity)

4: On your main screen, leave the "1" box empty on your action bar.
4b: On ALL your clones, drag your newly created "follow-assist" macro to the "1" box on the action bar.

5: Activate your key distribution program, assign it to all your active wow windows and press the "1" key.. All your clones should now display "Following xxx" on the screen.

6: Target something and hit the "1" key again.. All your clones should now target the same thing.

Badaboom.. you're ready to rock.. Every time you prepare to move.. Hit the 1 key, just to ensure the guys are on your back, every time you're ready to attack, hit the 1 key to make sure they're looking at the same thing as you...