[Exim] Exim Passwd File

Dears

As you know exim search for file usually in /etc/exim/passwd for
password and SMTP
Authentication.

Problem is here. This file is as same as shadow file and usually copy
of this file working
Properly. however making copy of this file and put it on
/etc/exim/passwd is not solution
In enterprise environment because each time a user change his/her
password we need to put
another copy of shadow file in /etc/exim/passwd and symbol link to
shadow due permission problem
is not working.

Is any body know how it is possible to configure exim to use shadow
file without change the user
Permission on shadow to read.

Any help is appreciated.

Best regards
MO