Ajenti & Exim: Outbound EHLO and IP for different domains

Hello,

I have been reading a lot on how to make Exim go through different interfaces and show different hostnames while sending e-mails, and I mostly see advice to set it up properly in cPanel.

I have several interfaces on my server with different IPs (IPv4s and IPv6s), and one domain in particular needs to send e-mail through a particular interface (well, two: one IPv4 and one IPv6). As of now, all my e-mail has been marked as spam by Gmail, because I believe I am sending e-mail through another server than the inbound one (as Exim listens to all the interfaces).

My question is, is there a way, like in cPanel/WHM and DirectAdmin, to attribute different EHLO responses and outbound IPs to different domains? Is that a future development or should I cobble up together some rules?

Last question, if I do that, in which custom configuration box should I input all this?

Thanks! Keep up the great work!