[Dovecot] Authentication with many Windows AD

[Antonio Alberola]

Dear All,

I'm a new user of Dovecot and I need support with the authentication
process.
I use Dovecot 2.0.9 and Postfix 2.6.6 on host x86_64-redhat-linux-gnu
2.6.32-279.14.1.el6.x86_64 CentOS release 6.3 (Final)

I need to select the validation method depending on the user. I have users
that have to be authenticate with UNIX account, and I have others thats have
to be authenticate with Windows AD. For example, some sysadmins and special
accounts needs validate with Unix accounts. Other normal users have to
authenticate with Windows AD, I have many Windows controllers. Some users
authenticate to a specific Windows AD and other users are validated in
another one.

How I can do this?

Thank you very much.
 
Antonio Alberola