For visibility use a number list custom state on the page. Set the visibility condition on each question group to show the group if the question number is contained in the page state list of numbers (assuming there is a question number field)
Set your quiz group to show up depending on the random number element value
Research for learning resources how to use custom states
This is just an example of a group that I named Quiz 1 and where I created a custom state type number (named quiznumber). I then set the group to be hidden and to only show when the custom state is 1.