Using external storage as a link

Hi!
I am interested in an approach how to use the external link for collabora without Nextcloud. As I can see in the loolwsd.xml, there are three types of storage, namely file, wopi, webdav. Instead of them, for example, I want to use http://my.external.storage/test.doc to the link http://localhost:9980/loleaflet/dist/loleaflet.html.
Is it possible to use a direct link to my file, or just an extra layer approach like Nextcloud might be a suitable solution?