I'm an ISboxer user but for my mouseover macros I have a view macro that syncs the camera of my characters and then after hitting this key ISboxer broadcasts the next mouse click on all of my toons.

It is an ingame macro:

/Script SetView(4); SetView(4)

I have found 4 works best for me. You can try out other numbers to see how they do for you. You can use follow to make sure your toons are facing roughly the same area then on your leader move a few steps back so you are standing more stacked ontop of your slave toons. Then you can line up your cursor and look at your slave windows and make sure they are also moused over your herb node before you click on it.