Hello grasshoppers!

I am trying out one of the definitions in the grasshopper primer (page 82) on how to use the Sweep2Rail component.

I want to find a way to calculate what the maximum size of the radius of a pipe should be so that the pipes do not intersect with each other. I thought about finding the minimum distance between any two points of one list and then will divide that one by two.

So that is basically my main question: how can I extract the minimum distance between any 2 points within one list? (does it make a difference if they are not planar?)!!