Okay. I don't know the specific answer, but a TCP based protocol should mean you can set the number of connections to 1 to prevent more than one client connecting at a time. How you get that set in your server's WiFi settings, I don't know. You may have to dig into the library code to find that setting if it is not exposed as a user setting during Init().
Assuming you can limit client connections to 1, nothing other should be required to make your dream come true.
Here's a relevant article.
Good luck!