[Exim] create_directory

is it possible to have create_directory create part of the path as one
user ie mail, and other as the user?

example

/var/spool/mail/domain as mail
/var/spool/mail/domain/user as user

have looked through the docs and do not see anything that sticks out,
and am still searching the archives. will probably open up the source
code here in a second and see if i can find a way in there if i have
to.

thanks,
-pd