Good morning, @AnitaCunningham ...
The "Files" area of your course does not allow you to set permissions on the files such that only specific sections in your course can gain access to them. I think your suggestion of utilizing Announcements or Discussions is a good one.
Another idea that occurred to me was to use Groups. It might not be the most elegant and would take a little time to set up. You could create a Group Set in your course, and then within that Group Set, you could create groups that are the same names as your sections. You would assign your students to these groups. Then, you can go to their individual group home pages, and there you would see a "Files" area that is only for that particular group. Here are the four Guides on how to do all of this:
Anyway...hopefully this will give you some ideas to try. Sing out if you have any questions...thanks!