Magnetic Gameobject

Hey guys i was just curious about what the best way to make a magnetic type gameobject. I have a game where the players control paddles but also can shoot projectiles across the screen. I also have an ability to make the paddle magnetic( although it doesnt do anything yet), and i was wondering how to best make all enemy projectiles move towards the players paddle like it was being pulled by magnetic force.

Now the way i was thinking was to do a getgameobjectswithtag and do a sendmessage to all projectiles to lookat the paddle with a quaternion.slerp to make it slowly face the paddle but the problem would b that only the gameobjects that are spawned when the paddle gets set to magnetic will be pulled and any other projectiles that are instantiated will not get the sendmessage.

The only way i can think of then would b to lookup the gameobjectswithtag every frame while the paddle is magnetic( 10 sec duration) which to me doesnt sound like the best alternative. I am newer to scripting so my techniques are limited so if anyone knows a better more effiecent way to do this please share and/or if doing it this way could work let me know.

Thanks again!