[Zope] proxy roles on Product methods

Hi All, Is it possible to set proxy roles on methods located in Zope Products. I need to turn the View permission off on some folders so certain users can't see them in a sitemap (uses dtml-tree). However, I've got an edit_html method located in a Zope product that then needs to use stuff in one of the folders that has "View" set to off for that user (who's running edit_html). Thanks, Tom