Hi Leszek,
Can you please provide more information on how you add invitees and how you schedule a meeting. I am not sure I understand the following part:
messenger@webex.com>
To the individual account and they cannot see other participant on the list, so this is 1 to 1 email from webex.
Normally, if you schedule a meeting in Outlook and add WebEx portion of the meeting using productivity tools, your Outlook is sending that invitation to all the invitees, and as with any other Outlook invitation, invitees should be able to see the list of other invited people.
Now, when you are scheduling via WebEx Site and not using Outlook/PT, then there is no option to do this, and invitee will just receive 1:1 invitation.
I hope this explains the expected behavior.
Kind regards,
-Dejan