A movie I accidentally saw when I was a boy, tanker, murder, trap, poison

Hi everyone,

It was about 1995, I saw a group of adults watching an erotic movie. The plot is:

  • A lady (A) hitchhikes on a highway and takes a ride in a tanker truck.
  • A motor biker follows them.
  • The lady seduces the driver, and they stop at a barn/an abandoned house to have fun (erotic).
  • During that fun time, the biker tries to pour poison into the tank, which contains a drinkable liquid.
  • The liquid was then drunk by 3 other ladies, and they die.
  • Can’t remember what is going on next after this.
  • In another scene, the lady (A) is having fun (erotic) with another guy (probably the biker), probably to celebrate the successful murder. Outside the house, 3 ghosts are watching them (3 dead ladies).
  • The couple then moved to the outdoor swimming pool: the man goes first and gets killed by the ghosts, the lady (A) found his body and scream.

That’s all that I can remember. The movie was in VHS at around late 80s or early 90s.

Thank you for your help to find this movie.