This movie was from about 10 years or so ago. Seems like it was on Sci-Fi or Chiller. It was about some young friends driving. They got off the highway and went to this rest stop/park. There was a restroom at the top of a hill. There were stairs leading up the hill. There were weird people around here and there. One of the friends comes up missing. Then another. At one point there is a flea market at the bottom of the hill where these weird people are selling items. Then all but one, I think, of the friends has disappeared and the last one figures out that they are disappearing through a stall in the restroom and the weird people are going through the stall/stalls through the wall and living under the restroom and they kidnap people and make them work under there. I can’t really remember for sure. Thanks!