You can't tell LISTSERV that abc.xyz.edu is equal to XYZVM1. I've been
complaining about the lack of such a tag in BITEARN NODES for years, but
it's still not there and doesn't look like it's going to be there soon.
That USERDIR thing you were speaking about is either the WHOIS package
available from LISTSERV@PUCC, or the LISTSERV UDD that is now included in
the standard version, although not yet officially supported (I haven't
had time to write the NAD commands yet). Read the UDD-L archives for more
info.
Eric