[Exim] domain list from files in a directory

For virtual hosts I use a directory called "virtual" which contains alias
files named by the domain name:

virtual_aliases:
driver = redirect
allow_defer
allow_fail
domains = dsearch;CONFDIR/virtual
data = ${lookup{$local_part}lsearch*{CONFDIR/virtual/$domain}}
file_transport = address_file
no_more
pipe_transport = address_pipe
retry_use_local_part

So to add a new domain I just add a new alias file and add the domain to
my local_domains domainlist.

But, I'd like to generate the local_domains list by looking up the file names
in that CONFDIR/virtual directory. In other words, all files in the
virtual directory would be added to the list of local_domains.

Is there a way to do this? (Or perhaps a better approach all together?)

Oh, I'd also like to set the "user" for the pipe transport to be the
owner of the individual virtual alias file. Is that possible?

The goal is that I can just create a new virtual host by creating a new
file in the virtual directory, and that pipe transport runs as the same
user as the owner of the alias file (excluding root, if the alias file
happens to be owned by root).


Thanks,






--
Bill Moseley
moseley@???