Is it possible to add a Submit button to custom quiz slides in Captivate 8?

I have a variety of questions slides in Captivate 8 that are all custom-built with buttons and shapes. I had to do custom because there's a combination of Knowledge Checks and a Final Assessment, where only the Assessment needs to be sent to the LMS. Therefore, all knowledge checks and incorrect answers in the assessment do not actually count toward anything. (I understand in 9, there is a knowledge check option, but this is not available in 8).

Each "correct" answer in the final assessment is set to "include in quiz" -> "add to total" whenever it is clicked. This allows me to have a Results slide at the end of the quiz. Another reason I am doing custom quiz slides is because the built-in quiz slides require the user to click twice in order to view the feedback, which is not intuitive.

So basically, there's a button on top of each answer in the multiple choice, with the advanced action to either "Show [Incorrect Text] - Continue" or "Show [Correct Text] - Continue - Add to Quiz."

My client returned the module to me and asked if it's possible to add a Submit button to these questions instead of automatically counting whatever they clicked. Makes sense.

But I am having trouble getting this to work in a custom slide. I'm not even sure it's possible. I don't know how to "Add to Quiz" the correct answers depending on what is selected when the user hits "Submit." A thought crossed my mind to have each button set a variable 0 or 1, 0 for incorrect and 1 for correct. Then the Submit button can be a conditional that says, "If variable = 1, add 1 to quiz total." But I don't see how to do this in the actions panel.

Any ideas?