MFC - Deactivating all buttons except one

I have a legacy C++ MFC application with a complex GUI with Ribbons. I have a use case as follows : User clicks button A on a ribbon panel and does some work. After his work is done, before he can exercise the rest of the GUI controls, he absolutely must click button B on the same ribbon panel, and failing to click button B in this manner results in a crash if the user exercises some other controls.

Hence, in order to deal with this use case, I figured it would solve my problem if I could disable all of program's GUI controls in Button A's event handler except button B. Button B's event handler then enables the rest of the GUI controls. This way, I ensure that button B always gets pressed after button A.

Hence, my question to you is as follows : Is there a way to disable all GUI controls in one fell swoop, and then enable and disable controls individually?

I know how to enable or disable controls individually, but I have not yet come across an API that allows one to disable all controls.