I am going to explain how to do it in the sense that an enemy is attacking the player.
You put all enemy objects, enemyA enemyB enemyC into a family 'enemies'.
You add a family instance variable to enemies - 'damage'.
You add other logic, set enemyA.damage to 10, set enemyB.damage to 20, set enemyC.damage to 30 on created.
Then you have attack logic, enemies(family) on collision with player, subtract enemies.damage from player.