They either select Puerto Rico from the country list and leave the state field empty, or they select USA as the country and PR as the state.. the user is happy they've entered the data from their frame of reference. If the address is actually going to be mailed to our address standardization system does so to USPS specifications so it'll be converted to a PR state form of address.
>How the Puerto-Ricans using your system know, that they need to select USA as a country and PR as a state?