Actually, I figued it out. SMTPScriptingHost is actualy just a param, so if I needed to add additional listeners, I would just run the script like this:
C:\ cscript smtpreg.vbs /add 1 onarrival SMTPScriptingHost1 CDO.SS_SMTPOnArrivalSink "mail from=*@seconddomain.com"
This would create a second listener for the second email domain. And if you have more then just run the same line and change theSMTPScriptingHost to SMTPScriptingHost2, SMTPScriptingHost3 an so forth.
Once the listener is in, you can configure it to use the same EventSinkScript.vbs or a different one to use a different disclaimer clause. So to attach the action to the listener is:
C:\cscript smtpreg.vbs /setprop 1 onarrival SMTPScriptingHost1 Sink ScriptName "C:\EventSinkScript.vbs"
Works like a charm. I would love to use GFI but now its not free and my company is currently running on very tight financial budgets aka "CHEAP".