Tagging and extracting selected text from posts for separate display

Does anyone know of a plug-in or method to extract certain paragraphs from a post for display in a post combining the extracted texts from many posts?

For example suppose I have two posts each with four paragraphs of text 1-4. I want to be able to invisibly label or tag paragraph 2 in post 1 and paragraph 3 in Post 2 and then allow the reader to look for the label/tag to see only paragraph 2 and paragraph 3 text in a different post. If I use tag for each post the reader gets all of the text in each post by searching by tag, which I don’t want. In other words, I am looking for a “sub tag” that only applies to selected text in each post that can be searched for separately by that sub-tag.

Thank you.