The purpose of groups is to create custom modules that may be plugged into new circuits without the graphics overhead of using seperate objects. The Group and Pin Interface objects work together to define the new object.
Groups have two states, opened and olosed.
Open groups are mearly place-holders that define the name and contents of the new object. Pin Interfaces are also place-holders that define the pins and boundry of the new object. When a circuit with an opened group pasted into another circuit, it becomes a closed group and acts like a single object. The contents may viewed via the context menu. Controls inside the closed group may be adjusted, but the circuit may not otherwise be edited.