Tutorial - automatically enrol students into all main year group courses

I wanted a way to automatically enrol students of a particular year group into the main year group courses. So if I created a new (Year 4 history) course partway through the term it magically appeared in all Year 4 pupil accounts. This video turorial shows how I used http://drupal.org/project/og_multiple_mandatory_groups_by_role to achieve this. The result: if you (say)create a new (year4) course and then simply asign it to the Year4 role, then create a new course assignment, all fifty Year 4 students will have the course added and the homework automatically emailed to all of them. I hope it is of use.
http://video.google.co.uk/videoplay?docid=-996025370774379994