Bulk changes to visibility of files in a course

I have several courses in which I import a lot of files from the previous course. I do not want the files to be visible to the students until I choose to turn them on. When they import, they tend to keep the visibility setting they had in the last course (visible to all students). It would be nice to be able to turn that off for all the files I import in just a few clicks rather than having to reset the visibility for each file in the course one by one.