Add Feed Wants Username not Author

I'm trying to add feeds of external blogs. I create an author (say "Great Blogger") and then go to create a feed, plugging in the feed url. But when I go to change the author info from my name to "Great Blogger", the system refuses, because there is no "Great Blogger" user. I don't want to create a user account for every blog I aggregate; I thought that was what the Author construct was all about.

Any fix for this? The only way I've found around it is to manually create a blog post with "Great Blogger" as the author then cut-n-paste the blog item with my name.