This must the third time you've come to my rescue this week.
How strange! I already had my students and teacher in a Group. But I didn't activate Groupings because from what I understood that is for creating Groups of Groups, which I don't want.
I activated Groupings as you suggested and this resulted in me getting a new Groupings setting on the Quizport Unit settings page, see attached. Not like the one in your Quizport.
I didn't do anything to the Quizport settings because the options weren't viable, but now when my Non-Editing Teacher selects the gradebook she gets just the Group results!
Nothing in the documentation that I read indicated that you have to activate Groupings to get Groups to work in the gradebook............
Thanks so much Glenys!