Who is Andrew Cotton and Dana Grey from Violets Are Blue and what is their importance?

Andrew Cotton and Dana Grey are celebrities. When Cotton and Grey meet the Alexander brothers at the magic show in Las Vegas, they are easily seduced by the brothers and invite them to their luxury room. Once there, the brothers refuse use of recreations drugs and sex toys. They only bind the couple and drink their blood. The celebrity of the couple escalates the story in the national news. Cross begins to observe that the vampire killers only target physically beautiful victims.