Lotus Notes users are listed as Contacts in Exchange, so the Exchange users can address them easily and forwarding works.
Unfortunately, the Notes users reply back as email address from the Notes side, and not as this contact. So, when they are invited to a meeting as required (contact), the reply they send back comes from another person (email address), which auto-writes itself into the Optional field of the meeting.
End users may see the strange email address in the optional field and delete them, this of course sends a meeting cancellation.
Is there a way to bypass this, so Outlook knows that this email address is the person who was invited before?