[CS2] Layer Group
Layer Groups act as an organizational component for Layers. Layer Groups have a dark grey background, while layers have a light grey background.
If you open the "Group Position" section below the list of layers in the group you can control the position of all the layers in the group. So if you set the Left (X) value to 100, then all of the layers in the group would have their Left (X) at whatever their normal value is, plus 100.