This shot is rather interesting and have been meaning to try it again.
It involves 6 balls, and a rack.
Once you line this up, you will need to use extreme draw on the ball. It will pull the ball back towards the single ball lined at the side pocket. The impact to the rack will create enough force that it will send all 4 balls into the side pocket without interruption.
Video below to demonstrate.
Follow for shots, and more. I will post as time goes on.