I know this may quickly get complicated, just putting this out there for future consideration.
Designate a specific field in a deck that can be used for school-specific or study group specific content. In other words, make it so that some changes are published on a field-specific basis and people can subscribe to extra content/fields for certain decks.
Say I subscribe to the AnKing deck. Under the Anking deck, there is a list of other fields that I could subscribe to if I wanted. Maybe this is just extra content (Extra field that contains a youtube link to a free video explaining the topic, or some other resource) or maybe it is school-specific content (Extra field that contains a screenshot of the associated in-house lecture).
Would allow for opt-in expansion of current decks to include more content that deck maintainers may not care to add.
Would be hard (ie, dynamic editing of card types to add in user-dependent fields, sending deck suggestions to multiple maintainers depending on the field, etc).
I’m not sure if it would be better to integrate this into Ankihub directly, or build an add-on that somehow shows extra fields in one view (or combines two decks on ankihub via ankihubID in some other way).