Engaged in the topic of raising the SMTP server for the system.
And there was a good question - Is it possible to delegate not all the boxes, but one specific one in the MX?
UPD:
As an option in MX, specify the address of your server with a priority lower than that of others (if already delegated, for example, to google). But then the question arises that if it simply does not reach this MX (when the mail server will verify the sender's authenticity) or vice versa the previous servers will lie (then the letter sent to this box will come to my server, it will have to be sent to the normal recipient [of course, by timing] ], in the end, a whole pool of duplicates of the original letter may accumulate, and when this pool finally falls to the final recipient, it will receive a little).
PS
I hope I am writing clearly ^^
