Edge line particle hair in compositor?

I am trying to find a way to do toon style outlining on particle hair in cycles. Normally, this style is done with free style on polygonal hair. But freestyle only draws lines down each strand of the hair. For particle hair, where the outlines need to go is on the general shapes created by children clumping around a parent strand.

As you can see, the children clumping creates a tendril effect. I want to somehow get outlines around these tendrils.

Using dilate/erode and masks, I can get an external silhouette outline, but it does not handle the shapes that are on the inside, or areas where tendrils cross each other. I do not know if it is possible at all, but as I am only a novice with the compositor, I wanted to ask before giving up.

Does anyone know a way, or can theorize a way?

hair test.blend (536 KB)

I don’t know if this is the result that you want but I propose a pass with just hair and it’s alpha (ID pass too?). Then apply a blur then linear ramp to saturation. Alter ramp values for contrast.

In this messy version I had to pull a key from your art.