First, I would bet that flop. You've got a draw to the nut flush with 8 people in the hand. Easy, easy bet. Probably a 3bet if its raised. I think the hand plays differently after that. Second, what makes you think you were obviously beat on the turn? With so many players there are a lot of likely holdings that you are behind, but I don't think it's so obvious that you were beat. The way you played it the turn bet was good, but I'd probably just call down ui.