When setting up peer-reviewed assignments, it would be very useful to assign peer-reviewers automatically across groups to ensure that a person from group A is always assigned to a person from group B without having to do it manually every time (I am thinking of weekly assignments). 

The obvious use case for this would be to allow for a mentorship/critical friend relationship to be built between students who are taking the same course but are in different working groups (e.g. teacher training). In this sense, another option would be to allow for peer-review partners to be replicated for all peer-reviewed assignments, so that peer-reviewers would only need to be set up once.