Dr. Hiao-Tsiun Ma, a violinist, composer, and musicologist, fled China in 1936 and founded the Children’s Orchestra Society in New York in 1962. He faced the problem every children’s orchestra faces: the players are not at the same level, and a single score leaves most of them either lost or bored.
The usual solution is to filter. Audition, rank, admit the ones who can already play, and tell the rest to come back when they are better.