Default or wildcard virtual user with exim?

["John R. Ackermann N8UR" <jra@febo.com>]

I have a simple virtual user mail setup using exim 3 on a Debian testing 
box.  I have a director like so:

virtuals:
 driver = aliasfile
 domains = /etc/mail/virtuals
 file = /etc/mail/virtual-aliases
 search_type = lsearch
 include_domain
 no_more

and this works fine for the named mappings in the virtual-aliases file.

However, I'm getting a lot of frozen messages that are aimed at other, 
non-existent addresses in the aliased domains.  For example, 
"info@doofus.org".  These are probably spam messages, but I'd like the 
domain owners to deal with them rather than me.

I'd like to be able to do something like:

# virtual				real
joe@doofus.com		joe@real_domain
sam@doofus.com		sam@some_other_real_domain
*@doofus.com		admin@yet_another_real_domain

I've tried this syntax and it doesn't work with the director defined above. 
Is there a way to implement this kind of mapping?

Thanks,

John