Week 3: Mr. Drop Top Vs. Pikachu

"In thinking about my past week teaching what is one thing I would do differently, and why?"

The one thing I would change in my teaching is the way I group students. My classes have between 32 and 36 kids this semester and I have 7 cameras and 14 computers, so I have no choice but to group. 

Last week I put together a group that included a fairly large 5'6, 230 lb 15 year old boy with a 68 average in my class and he drives a red BMW drop top (this is important because he is SUPER entitled) The boy is having some disciple problems in other classes but is very respectful and protective of me in my class.Also, in that group is a 15 year old boy with 89 average in my class, 5'1, 90 lbs who has named himself Pikachu when we play kahoots. The group also included two other girls both with averages in the eighties. 
The group appeared to be working fine, every time I checked in on them no one had any complains, Mr. Drop Top didn't appear to be doing much work but Pikachu ensured me he was helping. The project had come to an end and for the entire week Pikachu had been taking up for MR. Drop Top. 
At the end of the project I always have students write me feedback on the project, generally it is a short form that asks how they contributed to the project, how group members contribute, and what the instructor can do to improve the project. Well when I saw Pikachu's feedback he informed me that students should be able to pick there own groups because some students "maybe threatened by other students to do their work for them". I felt so bad for Pikachu. 
So grouping is something I need to work on, but my questions is what do you do with the kids that can't work with anyone? How do they meet the standard?