I’d be sorely tempted to set up a database for this, with comments enabled and possibly a couple of plugin field types.

The database activity can allow you to have a structured dataset for the case study. It can also (optionally) require x number entries before viewing and/or allow x number of entries to be be deemed complete. Text entry fields will allow descriptive text to be added and conversation can be done with comments. You could also allow peer and educator review with ratings.

Custom field types like the Linked Checkbox, Linked RadioButton and Tag Input will allow grouping of similar entries - eg.. case 15, carew case, etc. - and these can optionally be shown to user with the Database Tags block and/or Database TagCloud filter. You can see an example of these additional field types, the block and the filter at http://practicelearning.info/mod/data/view.php?id=258. Note, this tagging functionality will be superseded this year by enhancements to the core tagging functionality, but that’s a few months off.

If you can DM me an extract of the current discussion (or give me an idea of the things that you would normally want to see covered on each response) I can create you a database preset to play with.