Actually yes, you can set it up so that it uses one parent category per menucard, and use their child categories to fill the menucard. If you take a look at the menucard.php file you can change the code to make it happen. You’ll have to delete and/or change some parts so I’d advice to only do it if you have experience with php.
Another way to do it is to name your categories with prefixes first so you can visually seperate them, and when it’s all set up you remove the prefixes. The categories will have the same name, but what matters is that they have a different id (for WordPress).
Hope this helps 🙂