Yes, it would save  a lot of I/O between LISTSERV  and MAILER. However in
your example the mailer would generate  only one spool file less (the two
PSUHMC recipients  could be grouped  in a  single file). In  other words,
there is not much bandwidth to be saved (unless your local links are 9.6k
BSC :-) ), but if CPU and I/O are a concern, go ahead.
 
  Eric