View Criteria: Only One Instance

I have a table with 500 stores. (StoreNumber, StoreZip, StoreOpenClosed [999 if store is closed, 1 if store is open])

I have a view that only selets the open stores

SELECT *
FROM tblStores
WHERE StoreOpenClosed <> 999

This selects all the open stores. There are 2 instances where there are two stores in the same zip code.

EX StoreNumber: 3452 Zip: 02192
EX StoreNUmber: 5325 Zip: 02192

I only want to select ONE store per zipcode. Maybe even select one of the two stores randomly. How could I do this with out hardcoding anything?

Thanks
Dynasty