Add popup within the ckeditor dialog box?
I don't know a custom module that can do this, I'll do like this:


Create a new content-type with an  entity reference, a trigger
string and a dialog text area.
In the referenced node, query for any referencing entities from the new content type. Most likely with a preprocess function and preferably in a newly created custom module.
Load referencing entities if found and attach a JS file that will receive the triggers and dialogue values through the settings array.
If all is well then JS file will have triggers in selectors and
dialogues to display.