getting a subdivided surface to react to a distance from a point

Hi again guys,

Still a newbie, trying to get a little something to work here.  So I have this surface that I've subdivided, I will eventually turn this into surface boxes, but before that happens I want them to react to their proximity to a point.  If too close to the point, the subsurface doesn't show up.  I think that I am on the right track:  I have the surface subdivided.  I take the centroid of the area of each subsurface for the first point of a distance calc.  I use a point that I define so I can move it around as the second point.  I plug that distance into a "larger than" operator and get a list of true/falses that look like they're doing what I want (see picture).  Now, how do I feed that back into the general method of creating surface boxes?  I think it has something to do with a cull set, but just cannot put the final piece of the puzzle in.  Any ideas?