Multi-week session labeling

We run multiple 6 week training programs concurrently. What I'd like to see upon creation of the event is a field which the schedulers can see so they easily know what week number the event is in. A simple counter showing:
1 of 6, 2 of 6, etc...

We initially had allowed drop-ins, but for scheduling we decided to block drop in sign ups and even rescheduling missed classes for the most part due to all the ways that can go horribly wrong. Having the label would make it easier for the schedulers to identify where in a session we are without having to open the event editing screen and see where we are. 

Going into the event an manually editing a custom field or a note to schedulers would be a very inefficient way of dealing with this.