[JONTEE]

I've recently added the above into my website and on the home page I'm going to be showing nine random images from three different category's. With each category split again into 6-8 sub categories. At the moment I can only pick one sub category out of the main category to randomly show an image from. I would like to select the whole main category to randomly search for an image, do you have any tips or can you suggest any additional mod to achieve this.