navigation links to pages that are protected

I am creating an online course with multiple lessons and lesson categories. I created a navigation with images, example, left arrow for previous lecture, right arrow for next lecture.
I made those pictures link to the correct lecture, but the lecture is obviously part of protected content. When I click the link, it redirects the user to the masked directory and of course there is nothing to be found and a generic No Access image.

Is there a way to setup multiple levels of protection and which ones have masks or not?
Or are there any other work-arounds?

Thanks!