Associating incoming emails to existing records ("set regarding")

Hi all - I have a simple requirement, I'm wondering if the only way to implement it is to write custom code, I was hoping for out-of-the-box:

1. I have a custom entity (Employee) that has an "email" field
2. I have a queue that receives emails
3. When the queue receives an email, I want to automatically "set regarding" to the Employee who sent it

To make this clear:

• There's a queue that receives emails on "hr@contoso.com"
• The employee "john.smith@contoso.com" sends an email to "hr@contoso.com"
• John Smith is not a user of the system, but there's an employee record "John Smith" with its email set to "john.smith@contoso.com"
• I want the received email to have the "regarding" field set to "John Smith".

Is there a way to do this only through configuration?

Thank you!!