Team efforts.

When people see one another's skills and can come to have confidence in and rely on each other, that builds bonds. Creative exercises are good ways to achieve this. Co-producing a play or video, painting a room, or making a meal (while not hungry, of course) could be methods that help kids to practice this. We take our kids camping and there are lots of ways for kids to work together and rely on each other. Also, opportunities to exercise independent competence and to do tasks that help the family.

Trauma bonding is a dicier strategy. Could work out. Could end in tears. It all depends how many times you want to have them survive a winter plane crash on a mountainside. By the third time, they'd probably catch on.