This has actually been round for quite a while, well you'll find it in 2.3. Can't remember when it was added.
It works in tandem with the Requirements::combine_files() function. You define which files you would like to group like
Requirements::combine_files('myapp.js', array('myapp1.js', 'myapp2.js'));
and it will combine myapp1 and myapp2 into myapp. Its not documented on http://doc.silverstripe.org/doku.php?id=requirements so I don't blame anyone for not seeing this functionality before!.
Edit: added some documentation to that page - http://doc.silverstripe.org/doku.php?id=requirements#combining_files
One piece of functionality I don't like is on devmode it doesn't default back to including each individual file, it just returns false so you need to include your files the standard way, then include that line after it.