How do I make the bullet only hit the targeted object?

Let's say I have this homing missile turret aiming at this sprite. Now example there are more same sprites in the way, how do I make the bullet not hit them and only hit the targeted sprite.

Store the UID of the target - say as an instance variable on the bullet - and when the bullet collides with a sprite you can check its UID and see if it matches the stored value.