To Bcc (blind carbon copy) someone in a meeting request in Outlook add that person as a Resource in the meeting request.
Whoever you add as a Resource receives the meeting request and can accept or reject it, but other people you invite to the meeting don’t see that person on the list of attendees.
TIP: If you’ve already added the recipients you want to Bcc as attendees, click the icon to the left of their name, and then click Resource (Room or Equipment).