Connecting two Voronoi balls

Hello!

I have to make little tubes as 3d connections between closest points of two spheres with Voronoi structure on them. I made this pretty naive, but it worked on two simpe spheres with Populate Geometry on them.

In my case there are too much connections and they don't go directly to the opposite or near opposite point, but do whatever they want. If I try to remove those lines which are longer for example as 1700 units, they all disapper. 

I would very happy to know, how to make good short connections, and if someone add a link how to give them volume or name a funktion, I will be also very grateful.