I've simply used 8 directions UP/DOWN for my test. my eleven players are all clone of the same object. i need them to move up or down at the same time.
i've used bullet for the ball with bounced on solid on. So that the ball bounced on the players.
The probleme is that when the players hit a wall, the nearest stop but the others continu to move towards the wall.
<img src="http://osiris.ibems.com/ground.png" border="0" />