Calendars for two people with overlapping schedules?

I was wondering if someone could tell me if there's a method in
Outlook 2000 to deal with my situation. Here's my scenario:

I work for two different people in the same office. About 75% of
their appointments are joint. But the other 25% is their own personal
stuff which they don't necessarily want the other to see because it's
personal. I'm very nervous about maintaining two different calendars
because that allows a lot of opportunity to schedule something and
have it conflict on the other calendar.

I guess I'm asking whether or not there's a way to maintain one
calendar where I can designate certain appointments as being for only
one guy or the other, or joint so that I could be like, "I'm going to
print out Steve' calendar," and he wouldn't be looking at any of
Pete's appointments except for the ones that they were both supposed
to be in. And vice versa.

Also, one of my bosses is very enthusiastic about the "invite
attendees" button in Outlook. Unfortunately, I'm using Outlook 2000
and he's using Entourage for the Mac. Every time I use the invite
attendees button and it sends an e-mail to him, there's no button for
him to respond with. And there's an attachmet "winmail.dat." Now, I
understand that if people are getting that attachment, then you should
send in plain text. I've tried that and they still get the
attachment.

Any help would be appreciated. I've tried going to a lot of FAQ's,
but unfortunately, I'm kind of in the "I don't know what I don't know
phase."

Thanks,
Pete