All organizational tasks related to groups, sites and organization can be performed from Configuration > Organizations.
For example to create a new Group you will need to select the 'Add' button from the Configuration menu and place the newly created group into the Site of your choice.
once the group is created, select the 'Edit' > and click on 'Move Out '
Once done select the system's new group from the below menu
Check box if all access need to be removed before moving out.