Hello.
That's correct, you can track one quiz or survey within the project. One thing you might consider, though, is to use just Quizmaker (not Presenter) and incorporate Quizmaker's Blank Slide feature for your content. In other words, insert blank slides into your quiz for the content, with quiz questions in between. To the user, it will feel like separate quizzes. The final score when the user finishes would reflect all the quiz questions in the quiz. Here's the button you use to add a blank slide: