non-ldap aliases lookup q

I'm trying to add virtual mailman lists to my existing jamm install.
I've created the lists and put them into an aliases file (lets call it
mailman.aliases) 

 

When I send email to the new virtual list, it bounces with a user
unknown error, Where can I learn what the different maps
(virtual_aliases, virtual_transport, aliases, local_recipient_maps) do,
so I can figure out where to add the hash:mailman.aliases line to my
main.cf, or how do I get postfix to first check for an alias in ldap,
then check the file before bouncing the inbound email?

 

Thanks,

~duane