How to set up dual mail delivery?

Question

Mail server

Good afternoon. colleagues. I would like to know and clarify. Now we are introducing ZIMBRA OSE into the organization. Now mail works through Yandex mail for domain. ZIMBRA OSE operates in the same domain.ru domain as Yandex.
It is configured in DNS by the following method:
Yandex 10 MX domain.ru
ZIMBRA OSE 20 MX domain.ru
Is it possible to configure dual delivery so that letters come to both mail servers?
In general, the task is as follows: mail should reach two servers at once.

Answer 1

Explain this to the sending server. The sender chooses the first available mx with the highest priority and sends the message to him. Everything that happens to him next is your concern. If you want, you can put an intermediate postfix that will deliver a copy of the letter to each of your mail servers. For the sender, this will be one mx.