Multiple associated domains

Hi,

I've just added a second domain to a "Business Email" solution in the "Associated domain" tab.
Do I need to create aliases for every account with the second domain?

For instance, when my primary domain is "domain1.com" with email address "John@domain1.com".
After a while, I've added a second domain, "domain2.com". Will the system automatically forward all incoming mails send to "john@domain2.com" to "john@domain1.com"? Or do I need to create "john@domain2.com" as an alias?

Thanks in advance!