I think we're heading to a feasible "work around."
For the students in the Sex Education "section," create a Module. The only contents in that module should be Assignments and Quizzes. Make sure that you only assign them to the Sex Education "section." If you have content that ordinarily would be in a Page, make a non-graded, no submission Assignment.
When you limit Assignments and Quizzes to just one section of your course, your other students won't even see the titles. All they will see is the name of your Module. That's it.
Make sure that you are creating a "section" for those students, not a Canvas "group." Remember that "sections" are used to differentiate students in your course. "Groups" are for collaborative work.