Well, you could ask or "insist" that she has a desk by herself. This may sound isolating, but my son had the same problem, and he loved it when the teacher gave him his own table, set off a bit from the rest of the class. I think it freed him from distractions and temptations, and it made him feel "special". He did this in 2nd and 3rd also. He's just not one who could sit in a group.