I've been tearing my hair out searching for this info. In an attempt to help minimize damage if a clients' infected machine sends spam and puts all my clients on blacklists ( happened over the weekend), I was able to get a /29 IP (5 addresses) for my VPS server. I have found posts on setting up each domain to an IP. But since I have more than 5 domains, I was hoping I could create a virtual group and assign the IP address based on that, i.e.,

mail1.myserver.com xxx.xxx.xxx.1
mail.domain1.com
mail.domain2.com

mail2.myserver.com xxx.xxx.xxx.2
mail.domain3.com
mail.domain4.com
mail.domain5.com

and so on. Can anyone point me in the right direction?

TIA,
Bob