Hi,
I'm suggesting to create virtualhosts (VH) for your JVMs (servers) ports (Environment-Virtual Host) not at the WebServer level. Then in your applications select different each VH.
By default there are 3 VH, admin_host, default_host and proxy_host. All new servers (JVM) ports are added to "default_host", and when you are deploying the application by default selected VH is "default_host".
If you create each VH to each JVM (server) you can serve request only by the ports selected in the VH.
Remember to change at application level VH and then regenerated and propagated the plugin.
Another option is to create VHs at WebServer level, that usually is done to attend request from the same IHS but different servernames (app1.company.com, app2.company.com,....)
Hope this helps. Tell us if you need more support.
Regards