Not a bad solutions, but doesn't really apply or work in a hosted solutions for multiple virtual PBX.
Why not? Asterisk is fairly configurable in all sorts of ways.
Something as simple as having two group of users that can't dial each other by extensions, but that use the same extensions for example.
So, multiple virtual PBX, all of witch would have possible different feature groups can't be done.
The list is very long, but that's just one example.
