Automatically Add User to Shopper Group Based on Location?

[Rabble]

I would like to offer free local pick up of products in my store.  I only want this option to show up for people who are near my store. 

Is it possible to automatically add someone to a shopper group during registration, based on their country/city/state/zip?

[Rabble]

Bump for info! 

[nd]

You could just set up a shipping method for in-store pickup and set it to the zip code range for your area.

Sorry for the mega bump, I had the same question but figured this would be an easier solution.