If you can enter all this in the form when you build it, you can use conditional logic to show specific values in your 2nd drop down, based on a selection in the first drop down (your state.) This will be a lot of conditional logic rules though, and will not be very easy to manage. You could do this with multiple forms, and make it look like one multi-page form. You would use the first form (first page) to select the state, then pass that information to form 2, where you can use the gform_pre_render filter to dynamically populate the 2nd drop down based on the state selection from form 1.
Here is the documentation for gform_pre_render:
And here is more information about dynamic population:
There is no simple way within the form builder to accomplish this, without conditional logic and a ton of rules.
The other way to do it, with one form, would be to use AJAX to dynamically change the 2nd drop down based on the selection in the first drop down. Here is how one user accomplished that:
Posted 8 years ago on Monday February 18, 2013 | Permalink