Customizing my records search

I have a customized page which takes the items records and makes a search based on particular values for a customized search of products.

Here is the page:

http://www.axislighting.com/CMS/search_products-test.php

I recently added another search criteria with the values of  light speed on the bottom. While that is working, I need to have this not interfere with the other search values. It should be independant of the top three. Right now you can do a drill down menu You can select Mounting, then further results with distribution then further with lamping. I want light speed to not be affected by top three options. 

How can I have it stand alone?

I am attaching both files.The search page and search results page, even though I believe you only need the search page

So in reality, I need when you click on light speed buttons, it should first clear all the filters above it (if they are selected) automatically. Is there a way to do that?