[Zope] Limited folderish objects

The Folder class offers quite a bit of the functionality which I need for a current project. However, what I'm attempting to create isn't a traditional folder for DTML objects, methods, etc. Instead, I'm creating a folder which contains subfolders which are intended for specific objects. The "available objects" list in the parent folder should only allow the creation of a certain type of object. So, how can I do this? I was told that I could modify the permissions on the folder to prevent other objects from being added, and this seems to be confirmed by what I managed to find out about filtered_meta_types, but I'm not sure. Can anyone offer any advice? Thanks.