Quote Originally Posted by Mercbeast View Post
Create a keybind, step 1, have it do an assistme action, and a keystroke action that outputs the key you bound with "interact with mousover". This will cause ALL of your minions to assist off of your mouseover and target whatever you've moused over.
... no, they are assisting off of your selected Target, that's what "have it do an assistme action" is doing. Your toons cannot determine your mouseover. WoW does not share your mouseover with other clients.