brookg : if you don't mind modifying theres no reason you cannot use the tweeter wires to power the mids\tweeters on the 6x9's.
Chances are, if you look under them by where you hook up, you'll see a second set of wires going to the terminals that are black and red. this is what you would need to cut and hook to. These 2 leads go to the mids\tweeters. this will 100% fix your problem. I assume your speakers look like this on the back
http://images.sonicelectronix.com/im.../big/r1693.jpg

the two silver go to the woofer, the red and black to the tweeter\mid. Simply cut the red and black off of the terminals and wire directly to them.