Group Curves by Proximity

I am working with a large set of Curves that I want to group via proximity.

There are probably many ways to do this, but i seem to have hit a wall. The curves that I have to start with are not ordered in any particular way, so I thought I would use a point from each curve as a way to use the native Gh Point Groups component.  So far so good, I am able to find the right distance where I can group the points correctly as seen in one of the examples...

but the problem is how do I use those groupings of points to go back and apply to the curves in the beginning of the definition.

My thought is that I would use the index item numbers out of the pointGroups component to create a data tree with the curves in order to group what I need.  I thought by using Andrew Heuman's TreeFrog components I could achieve the right data structure.  I am doing something wrong, but not sure where the problem/problems lie.

I am using a smaller set of curves for these examples. I intend work out a solution for a larger collection.

Any help is greatly appreciated.  I feel like I may be missing something straight forward.