I know that I can choose different transport agents (different SMTP servers) for different mail accounts. However, how to deliver messages larger than 10 MB using local SMTP server and smaller messages using an external service (e.g. Google SMTP servers)?
Is there any message size based transport policies? How to edit them?
The reason I want to do this since the external email provider I use for email delivery limits outgoing messages' size to a maximum of 10 MB each so I want to send those large messages using my own SMTP servers while all others using the external service.