Controlling multiple attractors (polylines)

Sorry for another post but I haven't been able to use grasshopper for a while and I'm a little rusty.  Are there any good examples of controlling multiple polylines as attractors?  I'm working with a wall installation and I am using the polylines (profiles of pedestrians and passing students) as attractors on this wall.  The distance measurement controlls the scaling of these flat circles so far; eventually I will make the circles actual openings in a surface mesh. 

My main problem is being able to get good control of the circle scaling with at least 3 profiles and maybe one of a passing car.  I want to control them in a way that you can actually see the silhouettes of the passing people.  The way I have it now for even one person basically looks like a gradient and that's not what I want.

This time I have attached files.  Thanks for the help.