Add custom link targets to "new post"-screen

Hi there!

I want to add a couple of new input fields to the wordpress “new post”-screen.

Let’s say I’ve got a bunch of custom post types (e.g. actor, movie). Let’s further say I’ve created a few published pages with these post types (“Cumberbatch”, “Hobbit”:wink:.

What I want to achieve is:

An editor can select a text within the wysiwyg editor, hit a button and start a search regarding the selected text within one ore more selected custom posts.

I doubt that there’s any plugin which will do exactly what I want, but can you point me into the right direction regarding the wordpress developer information on how to implement this?

Thanks in advance and best,