[exim] Forward router

Hello,

I used to have an Exim forward configuration that allowed me to forward
all messages with a 'reserved' username at any domain hosted in the
server to a predefined account, (ie postmaster@[anydomain] to
postmaster@serverdomain) but I lost it and now I can't achieve this
functionality.

Can you help me with this config?

Thank you in advance.
--
Mauricio L?pez Coria
SysAdmin & Dev
Maldonado - Uruguay