Drive with the healer.

Target the desired opponent to kill.
And repeat.
But if your toons start to move too far away, target a closer opponent.
So your toons will move (via IWT) closer to you.
This is optimal anyway, since you can then Death Grip a rogue (or similar toon) off of your healer and into the kill zone.

I also have the arrow keys set for slave only movement.
I frequently push down arrow (which is backwards movement) to break follow (or rather IWT running off).
You could bind anything you like for this, either a key or a mouse button.

I also have a hotkey for FTL Follow Me.
It is one of the mouse thumb buttons.
Which is very easy to push; if you watch any of my streams or the videos, you'll notice the purple/pink letters across the screen "FTL Follow" very frequently...