I would recommend building games for children through which they will see that one cannot succeed without the other children and that without them they would obtain nothing. This will teach them that...
Alone means weak,
Alone means small,
Alone means can’t.
It is just like a team game: There is great competition, but it is nonetheless a game where everyone depends on everyone else.
Gradually, children will learn from these examples just how much they need society, and how much they can benefit from a good society if they return its goodness.