Complex businesses can require multiple Google Apps domain instances to meet their needs. Previously, certain domain management functionality was restricted to primary domains only, making managing multiple domains a bit cumbersome. With today’s launch, Google is extending several key features to secondary domains to make managing multiple domain instances more seamless:

Check out the Help Center links below for more information.

Release track:
Rapid release and Scheduled release

For more information:
Custom app urls
Web address mapping
Group renaming