We are managing a Zimbra mail server Community edition. Since the IP Address reputation of our ISP is a bit poor, select domains (mail servers) are either blocking our emails which is resulting in loss of communication or mails not reaching .
However same domains have no issues receiving mass emails which were sent through a software using Amazon SES API.
Now we would like to send mails to select domains using Amazon SES API as an SMTP mail relay. However as far as users are concerned they should continue using MS outlook with current local Zimbra server as their SMTP.
We had earlier tried using another SMTP relay to send emails successfully using the same setup, but we don't know how we can use Amazon SES as a relay for select domains.
Note we don't want to send all mails using Amazon SES, only mails send to select domains, may be around 30 odd.
Any advice will be helpful.