I'm only playing 54s from the blinds or from LP after a ton of limpers, it's just not good enough if there is going to be a raise behind us.

I don't think you can play the hand any differently. IMO folding on the turn is not an option, even if you knew it was going to get capped you are getting the right price as you have 30% equity if you are up against a set. You are in trouble if there is a higher flush but given the action that doesn't seem probable.