This issue only needs to be tested in 1 device. Please notice that groups only affect the results, not answering the choice. When a user answers a choice, his answer is the same for all the groups he belongs to. Create 3 choices: one without groups, one with separate groups and one with visible groups. Make sure that students can view the results. The choice without groups should continue working as it should: you shouldn't see a group selector and users should see all the results. In the choice with visible groups, all students should be able to view all the groups. When viewing a group you should only see the results for the users that belong to that group. In the choice with separate groups, students should only be able to view their groups, editing teachers should view all groups. Please notice that, if a student doesn't belong to any group, he will see an error saying that he needs to belong to a group and he won't be able to view the results, but he will still be able to answer the choice. This can be a bit confusing, but I'm waiting to see what they decide in LMS in MDL-84462 so we can be consistent (right now LMS doesn't display any error).