AFAIK, this is an undocumented thing, but the Ctrl + F
search inside a document makes use of this feature under the hood
You can specify scopes to different documents in the search portal using isDescendant:<reference to the hierarchy you want>
. You can also combine these terms using space and that will perform on OR
operation. This whole this works when your search involves a tag (e.g. searching for todo
tags from specific documents)
Here is a demo