In the event of multiple brands on the same salesforce implementation, there are multiple support email addresses, which implement email-to-case, however in order to properly route the case to the right agent, you need to know the delivery address that the case was originally emailed to. How do you achieve this?
For example, support@sitea.com, support@siteb.com, support@sitec.com -- a user sends an email to support@sitea.com -- our routing for cases needs to be able to extract that this was sent to support@sitea.com so it can be routed to site a agents.