Ability to have property sources be dependent on another property

For example, if you have the source for one property be continents (like Europe, Africa, etc.) and then have another property be countries, having the ability to have the countries that show up only be the ones that you've marked as being in the chosen continent means that you wouldn’t have to search through every country.

This can have broader use cases, such as automatically populating other properties based on a single property.