attractor point

Hi!

 I want a list of linear-arrayed brep to change it's inner gapping (between each brep) according to a distant from a moving point on the same axis. with a max gap space (I guess that part I can do in c#).

like stretching an accordion instrument, and when the point is passing the final brep the system goes back to its starting point.

I'm having trouble with controlling the gradient gapping because if I multiply the attractors influence, the whole geometry jumps far away. 

-Niv