Excerpt of a paragraph as cross-reference

I have an InDesign book composed of various documents and do want to have in one document something like an index were I list some specific parts of text from the book like a preview (like an article preview on websites).

I could do it using table of content and defining special paragraph styles or using cross-reference using text-anchor or again paragraph styles ... BUT ... then the whole paragraph would be displayed or I do have to mark each and every part that should be displayed by hand cause I don't want the whole paragraph to appear. I only want some kind of teaser, like the first 20 words or 2 lines following a "... page 12"

Example:

Paragraph in the document:

Edis et enditation nihiliquam, et voluptium et ommod quibusam essequam esedi nat mo qui adicita aut porehenem idellente de nonsequodi audione ceruptae lam et maxime poriorrore seque cus, ipsus quodis inum re nonse nisquiam que nullabo. Ti sim ilita pelente velluptae nisquunt. 

What the preview-index should look like:

Edis et enditation nihiliquam, et voluptium et ommod quibusam essequam ... p. 12

Any suggestions? ... maybe there's a possibility with GREP or I simply missed some option somewhere.