Wrong section, but you're in luck. I think this is default functionality.
AddDamageType(%name, %Self Delete, %kill, %playerDamage, %vehicleDamage);
If a projectile does 100 damage, but has a damage type, then it will do 100 * %playerDamage to players and bots (horses, tank turrets), and 100 * %vehicleDamage to vehicles (Jeeps, Tank Bodies)