The Armoured Infantry book adds a new Special Unit Rule for use with armoured and motorized infantry.
Firepower Suppression
Units with a large number of automatic weapons can cause more suppression than other units. Firepower Suppression is similar to Artillery Suppression, but applies only to Firepower attacks.
When fired at with Firepower Suppression, the target must roll more 6s than the firing unit or be suppressed.
Rules Update: Firepower Suppression has also been added to all infantry machine gun platoons to better model the suppressive effect of their fire.