To create a new host in G Suite:
From the Admin console Home page, go to Apps

Google Workspace

Gmail

Hosts.
- Click Add Route.
- Enter a route name. Use a name that helps you remember the route such as Webservio Message Routing System.
- Specify any email servers for the route.
- Select Multiple hosts, specify multiple primary and secondary hosts for load balancing and failover purposes.
- Primary - mailroute1.mailshelter.com:25 Load % = 100
- Secondary - mailroute2.mailshelter.com:25 Load% = 100
At the bottom, click Save.
It can take up to 24 hours for changes to propagate through the system. You can track changes in the Admin console audit log.