A frequent request in the Microsoft newsgroups is from users looking for a way to send out meeting requests for training sessions or benefits meetings with HR, where each employee can pick the session that fits their schedule. The selected meeting date needs to be added to the recipients calendar and the senders copy needs to have a list of the attendees.
Unfortunately Outlook doesn’t have the capability for creating this type of meeting request, but you can do nearly the same thing by creating the meetings in the calendar, then save each meeting as an ICS file on the hard drive. Send the invitees a message with each of the ICS files attached and instructions to choose the meeting they want to attend.
To avoid confusion, use the meeting date in the subject so the recipient only has to open the meeting they plan to attend.