Layered content within a particular lesson

When developing content to deliver online, it would nice to have layers.  Notice this screen shot from a course I am developing in Black Board for an online development course I am taking.  What I like is the "parent -child" layering.  Look at the content under Week 9.  I like being able to have folders under Week 9 and see the content that is in the folder and the student can click on the layer under the folder they need to be working on.  In Populi, everything is in just one page.  It makes it hard to distinguish  where and assignment is.  Also, I would love for the the external links to be within the content page where they are being assigned.  Often external content cannot have a name change and the list on the right  gets confusing.  Thanks!  Leslie