Need help with a definition

Hello! I'm a college student doing a work in grasshopper and I'm having a bit of a hard time getting the definition to work right, so I would appreciate any help you could give me. I've created a grid of points set on an horizontal surface and in each point a vertical cylinder rises. Then, I added a few components so that the height of the cylinders would vary according to a point that functions as an actractor. So far, this works, but when I tried to add more points as atractors the cylinders only reacted to the first point. So, my question is, how can I put the cylinders height reacting to a various points, a curve, a surface or a pipe?

Thanks