what a lot of indigenous societies learned about immigration is, only children born of mixed marriage with a local will have full rights of citizenship. others will be treated with dignity as guests so long as they abide by community standards.

the benefit of this is, it encourages mixed marriage, which increases the local gene pool and prevents future conflicts, because fewer people choose to wage war on their own family relations. at the same time it encourages acculturation by nurturing local cultural norms at a generational level.