You can re-categorize them to be worn with other types of outfits. Sims 2 Categorizer is available
here to re-categorize the stuff to suit your needs. Click on Sims 2 to the left on the screen and then select Programs. Scroll down to the bottom where you can see Sims 2 Categorizer.
Jfade's Wrangler program works in a similar fashion but it is not easy to use it. It's available at DJS.