There are three toggle button widgets, grouped together Pt_Group and set as Mutually exclusive so that Only one widget is allowed to be selected at an instant.
Is it ok to unrealize one of the toggle button widgets after the group has been displayed?
Probably, try it and see. If that widget is selected when you un-realize it, you probably won’t be able to select either of the other two. You might have to destroy it, which may not be what you want. Or you might be able to just de-select all of them first.