Currently I have a single server for Zimbra.
I am going to be adding on an MTA server (w/ antispam+antivirus) soon.
I would like to do is have the MTA be the primary MX and leave the MTA components on the server I have now.

I have 2 reasons for that:
1. I don't have to go and re-configure every single Outlook SMTP setting.
2. If the MTA has any issues, than the other server with the MTA component can continue receiving/delivering email.

From searching around I found many threads from many different times that don't completely answer the question on a setup like this. Most of those were from previous versions of Zimbra.

Looking through the Admin console does show that you can add in more than one webmail MTA.

Any problems or areas I should focus on for this?