final String message = messagePrefix + messagePosfix;
Recipient recipient = new Recipient(groupName, UserGroup.of(Person.convertToUsers(recievers)));
Sender sender = Bennu.getInstance().getSystemSender();
String gopEmailAddress = Installation.getInstance().getInstituitionalEmailAddress("gop");
new Message(sender, new ConcreteReplyTo(gopEmailAddress).asCollection(), recipient.asCollection(), subject, message, "");
}