Subdomins

[M. M. J. Weerasinghe]

I am having a problem as discussed below. I am maintaining a Internet/E-mail server. Suppose I have a Domain called "test.com" and there are several users getting Internet Email facility through this server. I want to group my E-mail users in departmental vise. So 10 users will get E-mail address like [EMAIL PROTECTED] Another 10 users will get E-mail addresses like [EMAIL PROTECTED] And for the other users as well. I am using Red Hat Linux 6.1 How shall I do this. Wellcome any hint   Thanks in advance   Jagath