This is a great question. It sounds like using the Content Privacy Settings, which are applied to folders in your library, would help you out. Privacy Settings allow you to decide from four options a security level for each folder in your Library. Check out the Content Privacy Levels article in the Help Center to learn about the options and how to apply them. If you're using the Beta Library, check out this article.
Have a great day and let me know if you have any other questions!