Intense Pathfinding 2 is very cool and it does have the enemies keep a place and so no other enemy will try to walk into that spot.
However deconstructing the code is beyond me. Though it looks like its a job between tracing and storing offset vector positions based on the target vector the enemies move to.
It makes sense, if a vector is taken, move to nearest vector. Rinse and repeat. I will try a basic version of this and add more and more enemies to it.
IP2 has some very cool functions in it that I could use though. I would recommend others to peruse the code, very well commented.