Offer Restrictions

Due to extenuating circumstances we will be offering a limited number of complimentary tickets to a number of specific out-of-town patrons. After discussing some options about the best way to do this I was asked if it was possible to give them a password and they could redeem online. The catch is, we don't want them giving out the password to all their friends and having everyone getting comp tickets! I was wondering if I build an inside source promoted to these people then create an offer for the performance, will it work online? Will it prevent other people from ordering these comps? Also, how will it work online? Will they have to log in to the system before their password will work? If this is much more complicated than I think it is please tell me and I'll tell the team to head back to the drawing board. Thanks!