Cascading List of Values with Drill Filters

Hi All,

        I have a requirement to have cascading LOV's for drill filters.

Example:

I have 2 Drill filters. Say , One for Country and one for state. When I select a country in the first drill filter I want to be able to see the states that are within the country in the drop down list of the second drill filter. 

But Now I see all states for all countries in the drop down irrespective of the contry selected.

I have set the hierarchies in the universe.. But it doesn't work on drill filters.

Please let me know if anyone has a solution for this.

Thanks!

Sharmila