Does anyone know of any examples dealing with "Drive Zones";

My client wants to search for items in our database within "60 minutes" drive time of an address.

Being that all of the address in my database are stored in SQL Server, the only way I can come up with is find the source zip code and then create a list of "nearby" zip codes and get all the addresses in the zip code list

example:

and ContactAddress.ZipCode in (77002, 77003, 77004, 77008, 77009 etc.)

So that brings up the obvious first question, is there a way to get a list of zip codes near a source zip code?

I know how to use the "map.ActiveRoute.Calculate()" method once I get a list of items, but I know I need to bring back a smaller list to accomplish this in a timely fashion.

Is there a better way using Mappoint to search for items in a "Drive Zone"; I thought I saw that somewhere but can't find it again. I think the old version of the software I am writing used a "Global Map" that had all of our contacts and all of our companies, but the code is impossible to decipher.

Also, I am using C#, so a C# example if possible.

Thank you,

Corby