Page Six:

"Holly and Bridget hate her," a friend of Wilkinson told Page Six. "They're totally jealous. She has her own empire now. She's got a clothing line, a modeling career and an exercise empire. They're just sitting there hangin' with Hef."

The friend expounds, "Kendra was never really Hef's girlfriend. She was cast for the show [E!'s 'The Girls Next Door'] because Bridget and Holly are old, and they needed a young hot girl for Hef. She was selected from a bunch of Playmate wannabes." Madison is 28, Marquardt, 34. Wilkinson celebrated her 21st birthday last year.

Wilkinson is said to be eyeing her exit from "The Girls Next Door" and the famed mansion next season. "She's definitely out," her friend said. "There are too many rules and Holly and Bridget want her gone. They're so mean to her."

Wilkinson has had a hard time sticking to the rules of the Playboy mansion - which include a curfew and a strict "no dating other men" line.

"She goes out all the time really late and parties," her pal says. "She's definitely been linked with other guys . . . She likes rappers and sports guys."

They were on the Heyman Hustle show without her recently.