Lookup field drop down values

I am trying to type in a zipcode and have city and state populate, and it's kind of working.  I'll explain.  I downloaded a csv file for all US zipcode and imported the data into formidable.  I set the zipcode field as a look up and city and state set as lookup and to watch the zipcode field.  since some zipcodes service multiple cities i set it up as a dropdown to show all cities , but the 1st choice is always blank.  even on zipcodes where there is only one city, the dropdown shows a blank entry 1st and the real entry second.  Is it possible to remove the blank entry for a dropdown field and show only the items found in the lookup? ( most are single, some will have multiple cities)  remember this is a lookup field so I cannot go into bulk options and remove a blank line.

here is a link to the form.

FrontPage

and a good test zipcode or multiple cities is 38583.  test your zip, even if it is a single it shows a blank line first.

any help would be greatly appreciated.

RLW