Line up one side of heavy tanks from one team, such as the Maus, a short drivable distance apart from each other. Each Maus or other well-armored tank should be about 5 tank lengths away from each other.
The second team will practice swarming into each enemy tank, one at a time, and shoot them until they are dead. After one tank is dead, the team will move on and attack the next tank.
The defend tanks will not fire back, just sit and be shot at, until the attacking team has learned the method.
Next, have the defending tanks moving, or place them behind cover or in other terrain.
Last, have each defending tank moving and firing at the attacking tanks to test real battle conditions.