Exim setup, virtual domains

Hello, I'm slowly working on getting an exim install up and running. I haven't done anything like this before, and have a question about virtual domains. The instructions here: https://www.afp548.com/Articles/Jaguar/exim410.html give "afp547.com and afp546.com" as examples of two domains. My questions is, would store.afp547.com and, say, orders.afp547.com qualify as two different domains? Or can I skip that part of the instructions for modifying the configure file? Many thanks in advance, Hugo Heriz-Smith