Efficient way to add a large number of "is equal to" values for branching/conditional logic?

I want to create a form that asks a visitor to provide their zip code to see if my product is available in their metro area. Since our availability is by metro area, I’ve got about 30 zip codes to load in. (I’ve only got one metro area right now, but we will add more.) 

It seems like I have to add “If [zip code] is equal to [#####]” for each individual zip code (using OR logic)… is there another way I can add a large number of values?

Thank you, community!