getting data based on another field in DCT

msa02

Could somebody please help me out in this issue.

In my dct I have a 'regions' dropdown pre-populated list resulting from an inline database call. Now there is another field called countries which I want to be associated with a button (a cgi callout) which would pop-up a window with dropdown list of countries from the database, based on the user selection in the 'regions' field.

I'm sure most of your would have done so. Can you help me out please!

I'm using 5.0.1templating version. I know it could be done easily in 5.5.0 but we will be upgrading to the newer version only by the end of this year.

Thanks!
Shams