Sometimes when I send a meeting announcement to a large group of people, I don't need to know who accepts or declines. I could just send an email message to the group announcing the meeting, but I'd like to make it easy for group members to get the meeting on their calendar. Is there a way to set a property when I plan a meeting so that the responses don't come back to the organizer?

There is such a property, and you can toggle it off and on with the Request Responses command on the Actions menu. You might have to click the double chevron at the bottom of the menu to display that command.