code: void collectVertices(final List<ManagementVertex> vertices) {
  
  		final Iterator<ManagementGroupVertex> it = this.groupVertices.iterator();
  
  		while (it.hasNext()) {
  			it.next().collectVertices(vertices);
  		}
  	}
docs: Adds all management vertices contained in this stage's group vertices to the given list.
  
  @param vertices
  the list to which the vertices in this stage shall be added