Apps That Need To Exist: Local Etiquettr

I could really use a GMail plugin that sorts, separates and color-codes my New York City contacts and my North Carolina contacts.  That way, when I see a blue email, I know the sender’s in NYC, and not waste anyone’s time on a response unless there’s a problem or  important changes to convey. When I get a yellow message, I know the sender’s from North Carolina, so it’s only decent to write back to thank the sender for their message telling me they got my email.