I don't use modifiers in my macros. I have a Disc Priest that leads 3 Hunters on one of my teams. I've got three bears that act as the tanks, so healing multiple tanks drains my mana fast, but I use Healbot on my main which happens to be the Priest. I've got my Hunters macros to /assist whatever I have selected on my Priest, but I use Healbot so I don't deselect my targets. You can use the addon's window to click heal anyone in your party. You can also set it up to where each mouse click does something different. Very effective tool for my setup. Most people run with a healer on /follow and another window as a slave, not me, I started this way since my main Priest was already on my main account. Give it a shot if you haven't already. Takes some of the stress out of figuring out the macro system.