How to link an account to a specific recipient?

Question

Email

There are two accounts, internal and external. It is necessary to configure so that the internal account sends to the internal address, and from the external one sends to the external address. And then you have to send reports to each recipient separately by creating a message.
I don’t know how to do this, but the program needs to know from which account to send a letter to a specific recipient

Answer 1

can only be configured on MTA