sharing in Writer

Hi I am a teacher who is using writer with her students. I have 2 main questions.

1- I have 120 students in 6 different classes who are all sharing documents with me. Is there a way to organize the documents into folders so I can see only one class at a time?

2- Some kids have accidentally shared their document with me twice. It is the same document, no changes have been made to it. It shows up twice in my shared folders program. So, is there anyway I can delete one of them? Or do they have to go and cancel the sharing?

Thanks in advance.