A PolicyRule is designed to be used for a single purpose. Sometimes, a management system needs multiple separate policy decisions and actions to be conducted in concert. A PolicyGroup is a generalized aggregation container.  It enables PolicyRules and/or PolicyGroups to be aggregated in a single container. Note that loops, including the degenerate case of a PolicyGroup that contains itself, are not allowed when PolicyGroups contain other PolicyGroups. PolicyGroups do not have associated specifications, as they are “just” containers.<br/>A PolicyGroup, being a container, is a perfect way to distribute notifications of events to other components of the PolicyServer. This is done by associating one or more PolicyEvents with a PolicyGroup, as shown in Figure below.<br/>The ControlsExecutionOf association defines the PolicyEvent that controls the execution of PolicyRules in the PolicyGroup. It is implemented as an association class to enable a filtered subset of elements in the PolicyGroup (that are selected by the set of PolicyEvents received by each PolicyGroup) to be executed.<br/>