Many to Many dilema

I have Courses, Modules and Lessons.

A course can have many modules and a module can be in many courses. A module can have many lessons and a lesson can be in many modules.

3 tables (courses, modules, lessons) 2 pivots (course_module, lesson_module) [standard]

If I'm viewing a Lessons. How can I tell from which Model and Course it is?

What's the best way handle something like this?