If you dont understand the concept behind this go to this website:
http://store.summitracing.com/eadvse...earchType=Make
That site makes use of what you should do, it dynamically changes all dropdown boxes based upon your initial selection. As you make a selection from the dropdown, the (main) drop down disappears and is replaced with plain text, this prevents your users from making a bunch of selections, then going back and altering the main category.
(To allow for functionality that would allow a user to change categories on the fly like that isnt overly difficult but will be come a pain in the amount of records you are talking about.)
As joel said, buzzwords arent going to get you out of this; sure you COULD use XML, but the XML file would simply replace your database as your datasource. Simply put, the only way to remedy your problem is going to be to apply some sort of filtering on your resultsets.
"The one language all programmers understand is profanity."