Hierarchical Dependent Drop Down List???

[qanjorin]

So I currently have a great, working dependent drop down list, but I have to continually add new things to the second drop down and I now have at least 1,000 items for each section of my 1st drop down list. If that makes sense.

Drop Down 1
I created a table with the headers as the drop down list. There are 32 of these.

Drop Down 2
Each item underneath the header is in a drop down dependent on the first selection. Between 500-1500 under each of the headings, but can be separated under a sub-heading. I currently just have a space and then a title to separate the sections. I'd like to add the sub-headers into that drop-down as there are only 12 of those

What I need is to be able to essentially have sub-headers that appear in the Drop Down 2 dependent on Drop Down 1. And once I select the sub-header it will show the items within the sub-header. I only have around 20 different categories and it would eliminate the searching for the item in Drop Down 2. The only thing is that I do not want the sub-header to appear in the cell what-so-ever and I need to contain it to just those two cells. It should work like any sort of start menu on a PC where you can select/hover over programs and it opens up more selections.