How to setup postfix as MTA via gmail with delay?

Question

JavaScript

Good afternoon.
There is a billing system that sends out letters several times a month.
For mail messages there is a paid service from google apps. Unfortunately, Google has a limit on sending emails, something like 30 per minute. The billing system does not have settings for delaying sending, and when the appointed time comes, it makes a mass mailing, something around 3000 letters. Google bans us for this and letters do not reach customers. Of course, clients are happy, but I'm crying.)
While I'm working on the version of the postfix configuration as MTA.
So far, the question of how to set up sending messages in batches of 30 per minute is completely incomprehensible. Unfortunately, I had no experience with postfix. Please let me know if you have any ideas how to make this wish come true?
In general, I have nothing against "non-postfixes".
Thanks for the help!
PS I don't really want to leave Google, I bought it so as not to administer my own mailman.

Answer 1

The code written in does not create DOM elements, it contains plain text. You cannot access elements from it through js, because they do not exist (there is plain text).

Answer 2

Found a solution from Amazon - SES. I'll try to use it. If anyone has experience using it, please share :)