How to split news to: content for index news, full content

Hi all. I need to split the content of the news in 2 parts.

1 part is the part that I will show in the list of news in my index page.
then, when users will click on the news, I will show all the content.
So i need an invisible delimiter for the user, that allow me to track the content of the news for the index page.

How can I realize it in CKeditor? I only need to insert this invisible delimiter and then I will do everything on server side with PHP

Which is the best method? Is CKeditor already implementing it?

Thank you very much