Every fast break drill has a little bit of defence and rebounding, since in a game you have to defend, rebound, then run. Get committed to the transition from defence to offence.
Five players are in the lane facing coach, with the guards up top and 5 in the middle. On "stance", the players yell "defence", slap the floor, foot fire with palms up, coach throws a ball up, they turn, rebound and break to the other basket (primary or secondary break). Create an advantage (separation) in the first two steps.