I have a document type “Blog” with child documents of type “Comment”. I want to create a separate collection in the backoffice that displays all comments regardless of which blog post they belong to.
To my knowledge that functionality doesn’t exist out of the box. Content nodes can’t live in two places at the same time. A custom dashboard or section could be built:
You could then create a c# controller that returns the comment node data (as json), and have the dashboard request the c# url on load.