Possible to get calendars updated when users not logged in?

Using Outlook 2002 with Exchange 5.5 server.

Two secretaries have delegated rights to about 5 or 6 other user's
calendars. They manage all entries in the calendars for these users. However
when they schedule meetings, or change individual meetings, for these users
the new/changed entries do not appear in the calendars unless the users are
logged in with the Inbox open. even when the option to process all meeting
requests automatically is set. As there is a high amount of entries to
these calendars this is causing them great problems because they can't tell
if a time slot is vacant or not. The option to have them also open the
users' inboxes is non starter as they would have far too many windows open.
The only way out that I can think of is to chnage the delegation rights so
that meeting requests are also sent to the secretaries so that they are
ackowledged/processed. Does this sound right or does anyone have a better
solution.

Apparently this system worked perfectly well on another system with Outlook
98 & Exchange 5.5.

m i k e x x