Google Message Security for Google Apps Administration Guide - Manual (Page 26)

26 Message Security for Google Apps Administration Guide
Hierarchy with Multiple User Orgs
If some users have unique service requirements, you can create additional orgs,
and configure them with the unique settings. As new Google Apps users are
added, move these users to the appropriate sub-organization. Each user receives
the filtering, services, and administrators defined for its organization. For example,
you might separate users in your New York and La Honda offices to give each
group its own administrator and support address.
Multiple User Orgs Users in New York and La Honda need different filtering, so
they’re divided into sub-orgs. As a new user is created, move the user into the
appropriate sub-org.
Create as many orgs as you want, and as many levels deep. For guidelines on
arranging users in organizations, see “Plan Your Organization Hierarchy” on
page 26.
Plan Your Organization Hierarchy
Initially, your service is set up with only one user organization. If all of your users
have the same filtering, services, and administrators, configure that org
accordingly and place all your users in it.
In large organizations, however, users will have different needs. The Sales
department might want more lenient spam filtering. The New York office might
have its own administrator and support address. You might want to enable the
Message Center for some users, but not for others. And so on. To tailor service for
groups of users, place them in separate orgs, and configure each org for those
users.