More anecdotes: Two friends with twins (11 YO, one same sex, one mixed), both have ended up moving one of the pair out of their neighbourhood school. Kids are always pretty (frighteningly) aware of differences amongst them, I've found. In both these families, the kids seem to have found it fairly easy to recognize/ accept that different needs necessitated different environments.
While it is uniquely hard to separate twins, both families have also found advantages in the way it has allowed each child to more easily and comfortably be themselves. So in some ways, the twins have become closer, enjoying each other more with less comparing/ competing, and more ability to draw on unique pools of friends.
