Unfortunately, there is currently no way to do this; There are a lot of ways you could make the process relatively painless, and I could definitely script it for you, except for one thing; when you unload the buffer of a fugitive-revision
in diff mode, fugitive bends over backwards (tpope's own words) to stop the diff in the original file for you.
I really like the behaviour you're proposing, so I went ahead and submitted an issue to the project on GitHub. Tpope willing, this will be addressed soon, and I'll be more than happy to post a script that will completely automate this behaviour then.