code: private void collectConfigs(GroupHierarchyConfig hierarchyConfig, List<CreateServerConfig> serverConfigs) {
          hierarchyConfig.getSubitems().stream().forEach(config -> {
              if (config instanceof ServerConfig) {
                  serverConfigs.addAll(Arrays.asList(((ServerConfig)config).getServerConfig()));
              } else {
                  collectConfigs((GroupHierarchyConfig) config, serverConfigs);
              }
          });
      }
docs: Collect server configs in current group
  @param hierarchyConfig group hierarchy config
  @param serverConfigs list with server configs