I've created a Google map that loads a KML file as an overlay. It is a map of trailheads for say hiking. What I'm trying to figure out now is how to create a search that will allow visitors to search within the KML's data and show the relevant trailhead/s as results on the Google Map. Is this possible? I have a google search that will let them search for an address, but this does NOT search within the KML file's data for a trailhead.

Ideally the visitor could input an address, say 12345 Main st., Chicago, IL, or something and it would display results that are within a specified vicinity, say ten miles, of that address (ie latitude, longitude). 

I'm a little lost as to even where to begin.

thanks for your help!

Davis