How to implement mailing letters through the mail client?

Question

Mail server

Given:
30 mailboxes
One of the mailboxes with a large volume of outgoing mail, which exceeds the limits of free mail hosts such as Yandex traffic rules.
120-150 letters are sent from this box a day, the number of recipients in one letter is up to 90 recipients, 5 people work with the box, everyone uses The Bat!
The rest of the boxes do not support the restrictions of the same Yandex and could well live there.
Now mail is hosted on timeweb, but their smtp servers are constantly blacklisted and the question arose where to go?
Is it possible to transfer all mail to Yandex, and set up some external smtp server like smtp2go for this loaded mailbox, and what problems can arise in this case?

Answer 1

I would recommend you to raise your mail server with a mailing list server. And judging by the approach to working with mail and questions, you would be better off hiring a specialist.