code: public void addGroupElement(final String groupName, final MetadataElement groupElement) {
          for (MetadataItem item : groupList) {
              if (item.getName().equals(groupName) && item.getNamespace().equals(getCurrentNamespace())) {
                  item.getElements().add(groupElement);
                  return;
              }
          }
  
          final MetadataItem newItem = new MetadataItem(groupName);
          newItem.getElements().add(groupElement);
          newItem.setNamespace(getCurrentNamespace());
          newItem.setSchemaName(getCurrentSchmema());
          newItem.setPackageApi(getCurrentPackageApi());
          newItem.setPackageImpl(getCurrentPackageImpl());
          groupList.add(newItem);
      }
docs: Adds a new element to the specific group element class. If no group element class is found, then a new group
  element class. will be created.
  
  @param groupName
  the group class name of
  @param groupElement
  the new element to be added.