Jetty is the java web server used for vCD.
There is an IP Address Handler built-in there, see:IP Access Handler
I suppose you can just add what you like to the jetty-ipaccess.xml file, see: https://eclipse.googlesource.com/jetty/org.eclipse.jetty.project/+/f451a14e0407463a2d44e8de80107a340d0c72b6/jetty-server/src/main/config/etc/jetty-ipaccess.xml
But not sure if this works, maybe just a hint which you can investigate further 