Although Diltoast has some good ideas, they really aren't that practical. The counselor idea is really the best one if ignoring Bob and company doesn't work. I would skip the dinner just because who needs the added drama. And there will be LOTS of other kids there too. Our middle schools each combine 2 or 3 elementary schools which make for 200 - 300 kids PER GRADE LEVEL or 500+ kids per school. Lots of people to put between you and "Bob". HTH a little and good luck!