How to fetch email address of inbound mail if it is an Unknown Contact

The requirement is that some fields must be defaulted if and only if the inbound mail address consists of/ends with @emerson.com . Oftentimes, the inbound email is an unknown contact. I noticed that this information does exist in the messages (refer to the screenshot).

Is there a way to fetch this information in Groovy so that I can check whether it ends with @emerson.comor not?