When hosting a party for my kids, I always invite a playmate for the birthday child's siblings. I find that it helps them cope with the fact that the birthday child has his/her mates around and they don't feel left out. Always works for me. Why not try it at your next party if you don't already do this.
Top Ten World Cinema: Forbidden Games a.k.a. Jeux interdits (1952, France) Director: Rene Clement The reason for its perceptively simple view of war-torn France is because of the story's touching perspective: Told from a child's point of view, she's at first resilient even to becoming an orphan, which makes her final and most gut-wrenching sadness over being separated from her little playmate, a tragedy personified.