Setting up Mail Server for multiple domains mapped to different ip addresses

We have taken dedicated hosting and using it for hosting multiple domains.

The different domains are mapped to different ip addresses.

for example

example1.com mapped to 1.0.0.1

and

example2.com mapped to 1.0.0.2

1.0.0.1 was the ip address that came initially with the hosting and we purchased and added another ip 1.0.0.2 later.

Right now postfix has been set up to deliver mails and configuration has been done in

/etc/postfix/virtual

to send mail for both domains to the same account (user1) like below:

[email protected] user1
[email protected] user1

The additional ip address were added using netplan by editing the 01-netcfg.yaml file as follows:

#This file describes the network interfaces available on your system
#For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    enp2s0:
      dhcp4: yes
      addresses: [1.0.0.1/22, 1.0.0.2/22, 69.64.50.12/22]

PROBLEM: The mail only arrives when sent to [email protected] i.e. the domain mapped to initial ip address 1.0.0.1 and not to [email protected] mapped to the additional ip address - 1.0.0.2

As already stated 1.0.0.1, 1.0.0.2 are just example ip addresses here