HELP! How can I authorize all three of my local subnet for SMTP?

[tbullock]

I am panicked so I hope I make sense.
Zimbra works fine from my desktop via Outlook and via the web.
The POP3 users in other buildings same LAN different subnet, cannot send mail via Outlook and SMTP. I think it is because they are on a subnetted segment separate from the Zimbra server.
How can I get Zimbra to recognize my two other subnets as allowed Relays?
Cheers,
Travis

[phoenix]

You need to add details to Postfix mynetworks, have a look at this post it should give you enough information to fix it.