A group 
is a folder that holds a number of computers.
You can create groups yourself or you can import Active Directory containers, with or without computers, and use them as computer groups in Enterprise Console. You can also set up synchronization with Active Directory so that new computers and containers as well as other changes in Active Directory are copied into Enterprise Console automatically.
Each group has settings for updating, anti-virus and HIPS protection, firewall protection, and so on. All the computers in a group should usually use these settings, which are called a “policy.”
A group can contain subgroups.