postfix virtual domain on specific IP address

We are running postfix with single domain (example.com) currently and we have appropriate PTR record for that.

Now we want to add one more domain but i want to isolate that domain totally, Even i want to isolate PTR record too. so we added new public IP address in same server and added PTR entry to abc.com

1. example.com - 1.1.1.1


2. abc.com - 2.2.2.2

How i am going to tell postfix run example.com on 1.1.1.1 ip address and abc.com on 2.2.2.2

so from outside if someone try to telnet on 25 port he get different appropriate domain for relevant IP.

$ telnet mail.example.com 25
Trying ::1...
Connected to mail.example.com.
Escape character is '^]'.
220 mail.example.com ESMTP Postfix

And for abc.com

$telnet mail.abc.com 25
Trying ::1...
Connected to mail.abc.com.
Escape character is '^]'.
220 mail.abc.com ESMTP Postfix