I've gotten around the single-user-access issue for my CEO's secretary
by setting up a copy job on the server to make a copy of his PST files
overnight, and pointed her profile to the copy. She only gets the
CEO's "yesterday" information, but that's still better than being
completely blind. As far as I know, there is no way to access them
simultaneously, as Roady pointed out.
HOWEVER: Since I've personally been the recipient of constant
chastising (all with my best interests at heart I'm sure) from this
group on this subject, I'll go ahead and point out that:
"Microsoft does NOT support personal folders stored on network drives"
So you should probably keep that in mind...
JeffG