anchor.diff:  %% -------------------------------------------------------------------
   all() ->
       [
  -        {group, single_node_groups},
  -        {group, two_nodes_groups},
  -        {group, three_nodes_groups}
  +%%        {group, single_node_groups},
  +        {group, two_nodes_groups}
  +%%        {group, three_nodes_groups}
       ].
   
   %% -------------------------------------------------------------------
  
positive.code:     ok = syn:join(GroupName, Pid1),
      ok = syn:join(GroupName, Pid2),
      ok = syn:join(GroupName, PidUnresponsive),
      %% call
      {Replies, BadPids} = syn:multi_call(GroupName, get_pid_name),
      %% check responses
  
negative.code:             single_node_callback_on_process_exit
          ]},
          {two_nodes_groups, [shuffle], [
  %%            two_nodes_join_monitor_and_unregister,
  %%            two_nodes_local_members,
  %%            two_nodes_publish,
  %%            two_nodes_local_publish,
              two_nodes_multicall
          ]},
          {three_nodes_groups, [shuffle], [
  