Could add postfix rate limiting feature?

Hello,
Could add postfix sen mail rate limiting?
Or I need manual edit postfix main.conf to set it?
Thanks a lot.

Thanks for reply.
If I want add mailgateway in front of imscp server.How to set it?

imscp server --send mail --> mail gateway --> to recipient mail server

The mail gateway can filter send mail content and control send speed.
How to setup imscp??

Thanks a lot.