Is it possible to organize forwarding of outgoing mail?

Question

gmail

Hello. Purely such a hypothetical question, is there such a possibility? Let's say there is mail "A" and mail "B" (both of them belong to the same person). And there is mail "C" belonging to a third party.

Question: is it possible to organize so that the owner of mail "A" could send an outgoing letter to mail address "C", but through mail "B", so that when the letter gets from mail "A" to mail "B", it was automatically sent on behalf of mail "B" to mail address "C"?

Answer 1

Create a rule on mailbox B, which forwards letters from A to C. If I understand the problem statement correctly)

Answer 2

How to send emails from a different address...