Can I set my email up so 2 (or more) accounts receive mail sent to 1 address ?

Yes. Create a forwarder from the account receiving the mail to the account that should also get the mail.

For example, if people are emailing abc@domain1.com but you also want xyz@domain2.com to receive that mail, set up a forwarder from abc@domain1.com to xyz@domain2.com, and both accounts will receive the email.

Tip: You can add as many forwarders as you want to get copies of the email sent to more accounts.