Hi,
you can controll them for example with instance-variables. For example if you need to destroy every enemy with "Health == 0" you just make an event where you compare the instance-variable health == 0 and then do an action destroy, which will destroy only the enmies with 0 HP.
Also you can give your sprite another ID like "enemyID" and then you have access to a special enemy with the "enemyID".