System-readmore problem: where to set ID item

Try this, publish menu item that points to category of that menu item. Set menu assignment for that menu item not to show those modules. You can put that menu item in some menu you will hide.

READMORE button that one can find here creates a brand new PHP page but I have no choice to assign anything to it.
The question remains: where can I tell the readmore button what kind of page I need (in order NOT to display video again)?
I found readmore "engine" in this file (editor_plugin.js) but I'm not able enough to handle that script. Thank You, very much.

Issue SOLVED.
Readmore has no parameters as it is intended always to load the same page showing also the readmore "hidden" content. If one needs to customize the page, a new article/item has to be created and the readmore button should NOT be the standard one but a simple hyperlink pointing to the new article.