generating closest destination

i was wondering if the current Google API will let me run proximity
searches.

for example, i have a database of start addresses and a database of
destination addresses. is it possible to have the API decide which of
the destination addresses is closest to the start address? i know i
could manually go in and mark which ones are closest to what in the
database, but if there's a ton of addresses, it'd be a lot easier if it
could be automated.

i was thinking (if searches are possible) i could send all the
addresses with the same state and have it return the one with the
closest zip code, or something like that.

so i guess i'm asking can you perform searches with the Google API, or
is this something i'm going to have to work out some other way?

thanks!