Creating Route 53 domains for an organization

You can share a domain across accounts by using the hosted zones feature in Route 53:

1. You create a hosted zone that has the same name as the subdomain that you want to route traffic for, such as acme.example.com.
2. You create records in the new hosted zone that define how you want to route traffic for the subdomain (acme.example.com) and its subdomains, such as backend.acme.example.com.
3. You get the name servers that Route 53 assigned to the new hosted zone when you created it.
4. You create a new NS record in the hosted zone for the domain (example.com), and you specify the four name servers that you got in step 3.

You can read more details about this process here: https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-routing-traffic-for-subdomains.html