How to generate activities by class, not by course in Activity Mangement

As per the present architecture of Activity Generator component, we can generate activities for all the classes of a course in a term at once. if a new class is created for a course for which the activities are already generated for the term the only way i found is by removing the activities using batch activtiy generator and re-generate the activities for all the classes of the course. The disadvantage of this approach is if the existing assessments already have assessments conducted and marks captured, we loose those marks.

Any one have different approach different from what i mentioned or any other work around(even a customization suggection also welcome) to achieve it in a better way