Keep the new members away from each other so they can't influence each other while they're learning to become part of the group. Have small groups of existing m

Keep the new members away from each other so they can't influence each other while they're learning to become part of the group. Have small groups of existing members mentor each newcomer until they've assimilated. If they can't learn to work with the group in a certain time frame, ban them so they don't start corrupting existing members. Maybe start a regimen of group chanting.