Treat document as a normal WP Custom post type

As a document management solution, this plugin ticks the boxes, but I have a need that when a user clicks on the document. Instead of showing the PDF (for example), it would instead display a page based on a template.
This would allow commenting on the document, adding more details, summary, supporting images etc. And importantly also have a link to the file itself.

I appreciate this would require a way to hook into the plugin where it takes over from normal WP functionality.

Can you help here? or point me in the right direction? Or am I just asking the impossible?

Manu thanks