I'm looking to extend a few plugins by adding custom shortcodes. These plugins create front-end pages, but I want to display that page content on another page. I figure there's an easy way to just take the entire php file that outputs the page data and wrap it in a function, but I'm not really sure how to start - where I should include the shortcode function and how I can get it to return the generated file. Thoughts?
(Eg: sabaidirectory create a directory dashboard page that solely outputs 'dashboard.php' to site.com/dashboard - I want that entire page to show up wherever I use [sabai-dashboard])