accessing $local in fastforward alias file

[Tristan Graham]

Hi,

I need to implement forwarding of the form user@somedomain -> 
user@someotherdomain. i.e. the original user at the original domain is 
propagated to the forwarded domain. Are there any mystical variables that 
can be used within the alias file ?

If anyone can help I would be most grateful,

Tristan Graham,
Inweb.