docs: protected Iterator findParentGroups(IEntity ent) throws GroupsException {
          if (log.isDebugEnabled()) log.debug(DEBUG_CLASS_NAME + ".findParentGroups(): for " + ent);
  
          List groups = new ArrayList();
          File root = getFileRoot(ent.getType());
          if (root != null) {
              File[] files = getAllFilesBelow(root);
  
              try {
                  for (int i = 0; i < files.length; i++) {
                      Collection ids = getEntityIdsFromFile(files[i]);
                      if (ids.contains(ent.getKey())) {
                          groups.add(find(files[i]));
                      }
                  }
              } catch (IOException ex) {
                  throw new GroupsException("Problem reading group files", ex);
              }
          }
  
          return groups.iterator();
      }