vCenter Enhanced Linked Mode allows you to log in to any single instance of vCenter Server and view and manage the inventories of all the vCenter Server systems in the group.
You can join up to 15 vCenter Server appliance deployments with vCenter Enhanced Linked Mode in a single vSphere Single Sign-On domain.
You can create a vCenter Enhanced Linked Mode group during the deployment of vCenter Server appliance.
You can also join a vCenter Enhanced Linked Mode group by moving, or repointing, a vCenter Server from one vSphere domain to another existing domain. See Repoint vCenter Server to Another vCenter Server in a Different Domain for information on repointing a vCenter Server node.