How to disable multiple mavlink access when is already occupied?

I use wifi on my drone for mavlink connections. I notice that my PC and ipad can get connected simultaneously, which is not secure. All I need is to prevent other GCSs from connecting to my drone when my PC/ipad have connected to it. How can I achieve this? I read mavlink_main.cpp and the other codes, but I cannot figure it out.

Can someone help me?