There is no difference in the installer for Xeams Community and Enterprise Edition. It will run as if you have purchased the Enterprise Edition for the first 30 days. It will then get converted to Community Edition unless a license is purchased.
Server modes in Xeams are not specific to any domain. Therefore, both domains need a "Forward To" value.
One workaround is to run the DevNull SMTP (https://xeams.com/DevNull.htm) on a machine and use that in the "Forward To"