How to implement a meeting between users with attendees and invite (RSVP not enough?)

Hi All,

I'm trying to implement the following scenario:
1. User A adds a meeting (Event) to her calendar and invites user B (email/message to buddy/user/email address, somewhat similar to RSVP module but in the event context in a single step)
2. The meeting is NOT visible to any other user at this stage
3. Only once user B accepts the meeting, the event shows up automatically on her calendar also, and both users are listed in the event details as attending the meeting

I cannot asume that these users belong to the same OG, and in many cases they are actually from different OG.

I've looked at the differnt Event related modules and postings and the Invite/RSVP ones but couldn't figure out how to do it.

Any guidance would be greatly appreciated. Thanks.