So I started dual boxing earlier today. I used RAF to make 2 additional accounts, downloaded Keyclone and got to work!
I didn't choose my characters based on good multi box setups. I just chose the 3 classes I felt like playing. Anyways, this is my current setup:

Pala is main char and focus target for my other chars. They have separate hotkeys.
I use this to follow the pala, and attack his target with all my chars:

/target focus
/follow
/assist
/stopcasting

It's working almost as planned. I'm able to attack with both my pala and warlock. But since the hunter is following my pala, it's too close to the target to shoot.

Any suggestions about how to make the hunter keep his distance?