Currently, group approvals in Checkpoints only allows / requires one person in the approval group to approve the checkpoint. The first person in the group to approve will be the only person to approve. So group checkpoint approval doesn't actually allow a group to approve.
It would be very valuable from a peer assessment point of view to have the option to allow each person in an approval group to comment and approve. The Checkpoint wouldn't be marked complete until all in the approval group have commented and approved.
Perhaps a toggle switch that would change group approval from "permission to approve' to 'required approval by all'.