Tallying question results: to building a sequence TicTacToe

I've started a TicTacToe template with 9 hot spots in each square, linking to a question. This is all done in one slide, multi layers. See sample file attached.

I ask participants to mark/score their answered squares. So within each square, I added a set of radial buttons to mark your team's "X or O's". This was the easiest solution I could come up with to track  questions that have already been answered and scored.

The problem I am having is that I am unable to keep a running total of "X's and O's", after continuing on to answer any of the next questions. (Example: After answering the first question.... I mark the square with an X,.....then proceed to next question, then answer.... The first X is no longer visible from the previous result.

I imagine there is some additonal coding involved here to retain previous marks.