Creating folder structure and giving folderwise permissions to user.

I want to create a three level folder stucture and in the last folder in each tree pages will be created and users will have permission to access the folder depending upon the permisions given to them. The user who has access to the parent folder should have access to all its child folders. And I want apply workflow to the pages the reviewers and publishers will change according to the folder in which the page is created.
How can I achieve this in drupal?