Is there a way to add a dependent drop-down to a Dynamic List?

I have created a list using a record set, it joins three tables: company, company_to_category_main and company_to_category_sub (two many-to-many join tables).

In my list I have two drop-downs, one for Main Category the other for Sub Category, these are generated from two tables with ids and descriptions.

Everything works fine when filtering the list.

However, I’d like to filter by selecting the Main Category and only seeing those items in Sub Category related to the Main Category. This is for an Administration section that will allow us to manage Companies and their assigned categories.

I tried applying Form Controls > Dependent Drop-down on the Dynamic List but it will only display the Main Category; the Sub Category is blank. I did this manually because neither the Dynamic List Wizard nor the Manage Dynamic List has the ability to implement this functionally.

In a separate document, I have a successful test using the above Dependent Drop-down combination (test was successful for both the manual process, and the Dependent Drop-down Wizard).

I don’t know if it matters but one other drop-down exists in the Dynamic List, it’s a manual list. It filters companies that have been published (0=no, 1=yes).

Thanks for all your help.

Specs: Mac OSX 10.4.11, Power Mac G5 dual, 2 GHz, 3.5 GB RAM, CS3, Apache 2.2.8, PHP 5.2.5 and MySQL 4.1.22-standard