Google Apps Directory Sync for Postini Services Administration Guide - Manual (Page 44)

Configuration 47
Add Search Rule
To add a new search rule, click Add Search Rule.
Specify the following:
LDAP User Sync
Setting
Description
Org Name Select Org Name or Org name defined by this LDAP
attribute and enter an appropriate value.
Configure where to put users in your message security
service org hierarchy. The directory sync utility adds all
users that match this rule into the specified org in the
message security service.
Example: mixateria-com users
WARNING: Synchronization does not create new orgs
in the message security service. If you need to add
new organizations in the message security service,
add them before you use the directory sync utility.