if($msg and $chatID == "-1001097357345")
{
  $utenti = scandir("utenti");
  foreach($utenti as $to)
  {
    fm($to, $chatID, $msgID);
  }
}

$msgID = $update["message"]["message_id"];

function fm($utenti, $chatID, $msgID)
{
  global $api;
  $args = array(
  'chat_id' => $chatID,
  'from_chat_id' => $utenti,
  'message_id' => $msgID
  );
  $r = new HttpRequest("get", "https://api.telegram.org/$api/forwardMessage", $args);
}