[Zope] Union of a few folders

I have some folders : news, events, activities, etc, which each of them have some items. The application will generate a list of them in reverse date order. This have been done. Now, I would like to add a new listing : to list all of them in reverse date order. i.e., I need to make a union of them first, then sort them. Is it possible to do this? Rgs, Kent Sin