Are you creating a control that hides/shows these pages in a navigation? It is kind hard to give suggestions without knowing the final result.
Is the state/province somehow stored in the URL of the site? If it is, you could create a control or a handler that could do what you are trying to achieve. Using your example, I also have an instance where a different CSS file needed to be loaded depending on what state the user is in. Fortunately, my URL has the state in it so my control that determines the CSS classes can pull the information based on the state. If this is the case, I should be able to help you further.
If you are wanting to setup these new properties on the create/edit page, it currenlty isn't possible. There are various posts on how to attempt to do this but they result in the new properties do not persist. I recently had a support question asking for this very thing and I received the following response:
Thank you for using our service!
There is no sample of doing this. We have a feature request logged. You can track it at the public URL bellow and vote for its popularity:
We are aware of the increased demand for this functionality, and are discussing its scheduling for the upcoming releases, so your feedback is indeed very much appreciated.