You can use the “tagged mail” feature for this.
Create a mailbox for sales@ an mails to sailes+europe@, sales+usa@ and so on will end up in that mailbox.
With the setting in the screenshot you can determine if the mails will be put into the subfolders “europe”, “usa”…, or if it should be added to the subject (or no speacial treatment).
The seperator is a “+” … unless you want to mess with the postfix configuration.