You can do anything you want with your post players as long as they react correctly to dribble penetration. We've said that before and it remains true. But, that leaves a lot of options. I thought it would be helpful to give you three that I would consider using if I had a 3 OUT team (or, if I had a team that occasionally flowed into a 3 OUT).
Place one post on the ball-side high post and the other on the weak-side low post. The High Post can be given rules in this situation: screen for cutters and shape up for the ball or set a ball screen every other pass (really, this can be whatever you want). The Low Post simply stays opposite the ball (allowing space for cutters to get to the basket) and whenever the High Post receives a shape up pass, ducks into the lane looking for the Hi-Lo.