well most of our courses are metacourses. The way it works is that when the user logs on, the moodle checks against a view of the SIMS database to see what course they belong to ( all 1400 courses are populated). If the class teacher wishes, they can populate that individual course with material. Some teachers/departments prefer to work collaboratively in which case they create a metacourse (say KS3 science, or Yr French homework) that is only populated with the relevant courses, and hence the relevant teachers/students.
Never seen this used in anger and would really like to.