Performers David Christopher (the guy with the unknown brunette), Frank Serrone (the guy with the blonde) and Kathlyn Moore (the blonde) are seen having sex at the final party. While they are doing this, they are also seen with masks on as regular party guests.
Actress Sarah Bernard's character is listed in the film's credits as an inconsequential "party girl". In fact, she plays "Deena Abbott" (the head of the Jabot Modeling Agency) who is an important non-sex character.