Hi there,
Thanks for writing in! The category pages follow the blog index template. We’re not able to provide custom development and what you are wanting to do is not a feature of X out of the box. If you are a confident dev, all the theme files that you need to look into are found in the “framework” and “views” folder (mostly in the views folder).
/wp-content/themes/x/framework/views
We apologize if we can’t provide much help in this area as it falls beyond the scope of our support. Thank you for understanding. Take Care!