Thanks guys, as I suspected. It sounds like something I've got to use a workaround for. I'm pretty surprised that it's not part of Vectorworks, seeing as class structure (layers) is absolutely fundamental to CAD standards within a company. Maybe I'll add it to the wishlist...
I'm not sure what the work group reference protocols are, they don't seem to show up in my documentation. I'll keep looking though.
My colleague was suggesting a similar method to your symbol method Dave, I was just hoping there was a simpler method.
I really can't understand why you can't get classes and layers out of the Resource Browser but still.
Jon