Assignment

hi all,

Is there a way to force students to deliver an assignment?

I have a course with 4 assignments. I would like to display the grades of students only when they have delivered all 4 assignments? If one of the assignment is missing then, either no grades are displayed or the course is failed.

I would like to go even one step further. Even when all assignments are delivered but just one of the assignments is failed (less than the half of maximum points) then no grades are shown.