Completion Limit

Correct me if I am wrong but when I am setting up a course, I have the ability to determine the number of modules which are needed for completion of a course.
However, it seems to me that what is more important than that is to select which of the modules are the required ones.

For example, I have a course with 15 modules in it.

Twelve are content modules and three are simply PDF files of instructor bios.

So, I do not want it to be a random twelve modules. I would like to specify the twelve content modules be required and the other three instructor bios to be optional.

I do not see a way to do this in a single course.

The only workaround I see at the moment is to make a separate course for required stuff and optional stuff and place both courses in a program.

That would seem really inefficient.

Am I missing something or can we add this functionality?