Calendar Series Event Attachments

I am trying to attach files to a calendar series event, but only for one of the events. I'm a student and I attach my readings to my calendar. I have created a series so that the course repeats itself for several weeks until the semester is over. When I try to attach the readings to one of the days it attaches it to all of them. This is counterproductive, as I could just open the folder containing all of my readings at that point. It would help me stay tremendously organized if I could create a series, and then attach files to specific events in the series.