Corners - Wrong player in the box

Hi!

I packed Lukaku Thunderstruck. I usally dont do a lot of goals on corners. But Lukaku is really OP. He made a goal about every second corner.

But then i packed both Diani and Katoto thunderstruck as well. I play Diani on RM and Katoto as ST next to Lukaku. 

But now all of a sudden Katoto is the perferd player in the box when taking corners. Guess its because she has even better stats than Lukaku on paper when it comes to headning. But she stands no chans against the CB of the oppisition!

Is it any tactical way to keep Katoto out of the box during corners? So that Lukaku once again can be the "big player" in the box during corners?

I would really appreciate your help!