Add attendees to Outlook based Zoom meeting

How can i successfully send invites to additional people for a Zoom meeting already sent out via the Outlook plugin?  This is what happened when i tried:

• I have created a Zoom meeting using the Outlook plugin.
• I sent it to one grouyp of attendees and started to get responces.
• I want to send an invitation to another group of attendees.
• I hit the 'Add or Remove Attendees botton.
• I added the new names/emails to the 'To' box. and hit  'Send Update.
• A dialogue box asked if i wanted to send to all or just those added (or deleted) I chose 'added'.
• So far so good.
• Then I hit OK.  It then said the message was replaced with the generic message!  So i changed it to the one I wanted and hit 'Send update' again.

It sent it to the whole list again!!  Ahh.

How should I have done it?