The Free/Busy feature allows users to view each other’s calendars for efficiently scheduling meetings. You can set up free/busy scheduling across ZCS and Microsoft Exchange servers.
To set free/busy interoperability, the Exchange systems must be set up, and the ZCS Global Config, COS and Account settings are configured.
In the Account Free/Busy Interop page, configure the foreign principal email address for the account. This sets up a mapping from the ZCS account to the corresponding object in the AD. This is a multi-value attribute, you can add more than one account address. A prefix is added to the address. .
In the individual Accounts>Advanced page you can change the O and OU used for a specific account. Usually this COS setting is correct.