[CoursePress Pro] Show course structure limited to chapters in CoursePress Pro

I have a page with [course_structure course_id=904]. This shows the entire course list (5 chapters, 10-15 units per chapter) - which goes pretty long down the page.
I want to break this up into tabs with each tab showing a Chapter with all units list, but I can't figure out how to limit the shortcode to chapters. I tried [course_structure course_id=904 chapter=1] for the heck of it, but no joy.
Can you give me a snippet that might allow me to do this?
Thanks.