Sorry about the confusion there. I misunderstood your question then. So as an example, what you are trying to do is

Toon A

Toon B

Toon C



Toon A sets focus to Toon B (let's say). So now you want toon C to be able to cast a spell on Toon A's focus, no matter what he has targetted currently? Is that what you are trying to do?