Disable ad listings for top-level categories?
i'm wondering if there is a way to disallow users from being able to post ads in top-level categories where several sub-categories exist. the reason for this request is that if i have a main Real Estate category with several sub-categories under it, i would like ads only to be submitted in the sub-categories and not the main category. is this possible to configure in the admin area or would this be something i need to customize in the php code somewhere?
ideally, it would be nice to have an option when creating new categories, to have a checkbox that reads something to the affect: "Allow ads in this Category?" but this would only affect the category chosen and not its sub-categories, unless any sub-categories also have the same checkbox option selected.
many thanks for your time and help,