One option on the ACK options would be to have a LISTSERV not send an acknowledgement unless it was the last of a set of peers. For instance, this note will enter the list at UIUCVMD. But UIUCVMD will pass it on to UGA, which will pass it on, and so forth.... Some peers, such as FRECP11, will not pass it on. If I know it got to FRECP11, I can assume it got to all the peers in between. There is a slight problem in that there are more than one end node in a list, so one might still get multiple acknowledgements, but it might be a better solution than the current situation.