ModeGroups serve as containers of Modes. The Modes in a ModeGroup are mutually exclusive. This means that only one Mode of a ModeGroup is active at any point in time. A precondition in the form of a Boolean expression is assigned to the ModeGroup so that ModeGroups can be switched on and off as a whole.<br/><br/>Semantics:<br/>The ModeGroup defines a set of modes of which exactly one is active if precondition is true and otherwise none is active.<br/>