How can I know wether a pushbutton is toggled or not?

Like seen on the picture, I have 96 pushbuttons initially green. Once clicked on a button ( toggled(bool) ) it becomes red.

What I want to do is to disable all red buttons once I click on the OK button.

How can I do that ?

If the OK button closes this window, what should I do so that the modifications ( disabled buttons ) are saved once I open the window again!