Add a new rule, “Groups”:

No Student shall have their own row in the GNDT, and as such there aren’t variables linked to a single stundent but only to Groups of students. Groups of Students will take one row each in the GNDT as if they were single Students and any Student may update any Group’s data via the GNDT, whenever the Ruleset permits it. There is a Special Group of Students, called the Class, which always contains all the students in the roster. Every Group of Students has a Members column in the GNDT containing the full list of the members of the Group. The Class’ Members field may be left empty for simplicity. Students that are not part of any group except the Class may add themselves to one of the groups “La Belle Equipe”, “Underachievers”, “Group nr.3” and “The Others”, chosen randomly between those with the least members. Unidling students join the groups they were in before idling, if they still exist. If a Group has ever one or less members, it ceases to exist.

Clear the GNDT.
Assign a row to the Class.
Randomly split all the students except the Professor in 4 groups as evenly as possible. Name the 4 groups “La Belle Equipe”, “Underachievers”, “Group nr.3” and “The Others”.

If the rule “Grading” exists, replace everything within it with:

Each Group of Students has a non-negative integer number of Achievements, tracked in the GNDT in the Achievements field as a comma-separated list of the first three letters of the title of the dynastic rules which awarded the Scores that made the Group gain each Achievement. New Groups start with no Achievements. If a Group would be awarded an Achievement that would create a double entry in its Achievements field, they don’t get the Achievement.
Rules can cause Students or Groups of Students to Score (by saying that the Student or Group Scores). Students and Groups cannot Score in any other manner. When a Student Scores they may post a Story Post within 24h saying to which of the groups they are a member of they want to assign the Achievement. That Group gains an Achievement, and the Student should brag about it in the blog post. When a Group Scores, they gain an Achievement. Achievements should not be awarded in any other manner.
This Rule takes precedence over other dynastic rules for the purpose of determining when or whether a Student Scores.

Set all the Groups’ Achievements to a blank string.