[This is a very narrow question, and I don't think it is covered in similar sounding questions]
I want to configure my server's DNS so that when someone sends email to email@example.com it is actually deliver it to firstname.lastname@example.org
Note: My question is whether this is possible to do ONLY with DNS not with myserver.com's own sendmail.
I think the answer is "NO" it is not possible, because when I add an MX record to DNS the email that was delivered to gmail's SMPT server would be TO: email@example.com and it would not know that account.
(But I hasten to add that I am just vaguely starting to grok how this all works.)