Proximty and MCs

Ok… bare with me as I am unsure what this technique is called.

I have three MCs in a proximty menu (ie when the mouse is close they go to the mouses position and follow it).

My question is, I want the MCs to be joined by a 1px line and when the MC moves the line stretches and moves with it…how do I do this?

This maybe a bad explanation so here is a link to back it up…

Click on the portfolio button to see what I mean.

Thanks
J_Mo