This can be accomplished using PowerShare's access privileges. The effect of changing privileges is not well documented and should be approached with caution. (Be sure to test before deployment.)
The following example shows how to protect one organization's catalog data from another organization in the same PowerShare system:
1) Open PowerShare Admin and with the Catalog Server selected in the
System Monitor window, select Show Catalog from the Window menu.
2) Create a new folder for each organization.
3) Select the newly created folders one at a time and restrict access by
selecting Access Privileges under the Catalog menu and then selecting
Folder Members from the pull down menu next to See Records.
4) Populate each folder with users belonging to the corresponding
organization. Note that original user records reside in these folders.
Aliases to these records will automatically be created in the Users and
Groups folder.
With this configuration users will find they will only have access to records in their own organization in the PowerShare browser. They will see names of people outside their organization in the Users and Groups folder but cannot open those business cards or send them mail since they lack the necessary privileges.
Support Information Services