I'm curious whether I'm missing out on anything here with the lack of using "focus". I make a macro named "Follower" and place it in all the alts' toolbars (key 3). My main has toolbar slot 3 empty. Key 2 is my opening attack and 4, 5 and 6 are for Ranged special, Melee special, and Nuke respectively. I use WASD to control the Main and unbind those keys on the alts. I bound the the arrow keys to control their movement instead (whenever its necessary) or move to an alt's screen and use both mouse buttons to walk/steer/position an individual alt. Per your example, my alts' Follow macro would be:

"Follower":
/assist Dzonatan
/follow Dzonatan
/assist Dzonatan

I've kept it short and simple like this, mainly because I'm still realtively new to the game, and haven't been able to dedicate a black Tuesday yet toward learning more about macros. I see that DrChaos posted about this earlier, but I thought I would expand on it to show my movement setups. Also, I discovered that adding another /assist to the beginning of the macro nearly eliminated the problem of my alts not always targeting my main's target.