If 1 is double-teamed, square the floor, with a player in the middle. If X3 rotates up to cover 4, 4 moves back to stretch the rotation. If 2 and 5 are denied, 3 gives himself up and finds an open area. If 1 passes, don't try to get the ball back to him, push or pass it ahead for a 3 on 2 or 4 on 3.
Use the same approach if trapped in the frontcourt.