[b]How to add virtual users account in sendmail[/b]

[cresameen]

Hi techies,
              I want  to host a real host and two virtual hosts in my redhat9 machine for internet.How can i set up mail server for each domain and how i have to add virtual user  email accounts in my mail server.
             One more thing i want to know is whether i can have different email servers for each domain and if so how can i do that or i can use one mailserver for all the hosts in the machine.
             This is my first assignment so somebody please help me.
             I am using sendmail .pl give the configuration details.
       THANKS