Ball owning 3x1 on two zones

Two zones are prepared, with at least 15-20 meters between them
On each one 3 ofensive players and one defender are placed
They have to maintain ball owning inside their square without the defender stealing the ball
The ball can be passed from zone to zone, but at least 3 or 4 touches have to be made
The player losing the ball or failing the pass, becomes the defender