Thanks. Yeah I realize this rigid structure really isn’t a good match, but I like Discourse too much to give up! We’ve looked at Moodle but it’s too confusing for the faculty and perhaps too rigid. We still want open discussion.
I’ve decided to go with creating custom groups, and restricting the categories and sub-categories permissions to only allow those with that custom group(s) (e.g. those in London get ‘London’ group, and also a custom group Course1 or whatever) to see the sub-category. This works perfectly as only those in group ‘London’ can see the London overall category, and only those with ‘Course1’ can see the course 1 discussions and subcategory, but we can still have great an open discussion amongst all the various course participants at the ‘London’ level. I also created a general category for all other discussion.
Since the site is invite only and one can easily add users to groups through the excel upload tool this method doesn’t add much to our workflow.
Thanks to all for the help.