Shutting Off iCal Invitations?

I love the ability to add attendants to events in iCal, it's super helpful for keeping track of who goes to which events. However, whenever I add everyone, iCal automatically sends out email invitations to them, even for events that have already occurred. Is there any way to turn off the auto-invites?

Cheers,
CJCS

Bump, this is driving me and everyone who's getting emails from me crazy!