Wow! You could try feeding the other kids something she LOVES but don't give her any. Just put her in the high chair and make her watch while they eat cup cakes or something. If she's anything like anyone else on this planet lol she'll eventually start getting jealous. When she asks for one - only give her a sliver. Just keep making her ask for more. If that doesn't work, I got nothing lol That's terrible that a little girl would starve herself like that! There has to be something else behind it. A child would not refuse to eat if they were hungry. Maybe she's not hungry, which would probably mean there is something wrong.
But I would try the jealous tactic. That works with everyone lol let me know how it goes