To have the Where dropdown on your website list specific areas instead of all of your tags, use location tags in OwnerRez.
In OwnerRez, add a location tag to each property using the prefix [l] (a lowercase L in square brackets, followed by a space), for example [l] Broken Bow or [l] Hochatown.
Only tags with that prefix appear as location options in the Where dropdown, and the prefix is removed from the label your guests see. Tags sync to your site automatically.