Outlook meeting requests/invitations - wrong recipients
 

When I and other colleagues send out meeting requests/invitations from our
office pcs, they seem to end up going to a lot of incorrect
recipients/invitees. Tried a suggested solution of clearing the tick box
under Tools/Opeions/Delegates, but most of us haven't even got any names in
the Delegates list!
Ordinary e-mails via Outlook seem to arrive at the correct destinations.
This problem has been going on for a while, apparently.
Any solutions?