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