Hi Kim,
this is an excellent idea! We had not thought of a "dynamic" summary of documents before.
The great news is that you can already create that in the current version by adding an iFrame to a formatted Markdown document and pointing that frame to the document that should be displayed. Here is an example:
All you need to change in the above example is the contents of "src". For that, just select "Copy Link" from the target document in Notebooks and paste that link as source. This is all. You can of course add any http link and thus integrate contents from the web.
We will see if we can provide a more comfortable way in a future update.
Thanks again and kind regards,
Alfons