Prompts driven by other prompts

Sometimes you want to be able to filter the values returned by a prompt based on a value you have entered on another prompt on the page. For example you have selected 'Australia' in the first prompt and now you want the second prompt to only list states for that country.

This example uses Pay Groups and Run Types:
When the user has selected a 'Pay Group' the prompt for 'Run Type' will only return run types that are in that pay group:

The first record stores the values, in this case it has no keys.
Note the key structure and list items on the two prompt records: