What's the best way to create a "teaser" without creating a full page

We often link to documents/press releases/blog posts from other organizations. I’d like to “tease” their story/release without fully republishing the content on our site. I still want that content to appear in my recent press release feed. When the user clicks on the link, however, I’d like to send them to a different site rather than a page within my site.

Can you suggest a way to get content to show up in list content without creating a stand-alone page?

Insert some items from a data file would probably be your best bet. Maybe you can get some inspiration from here:

https://github.com/spf13/hugo/blob/master/docs/layouts/index.html#L178