I’m interested in Binding URLs to different servers inside our network from one public IP. Typically this is done on the web server with a single IP and URLs are binded in the server config. Can this be done from the edge firewall with traffic inspection via mangle or something?
This is called a reverse proxy.
If you configure a host inside the network to be the reverse proxy, then forward ports 80 (and 443 if you’re doing SSL) to the reverse proxy host, and let it make proxy requests to the various internal servers based on the URL of the incoming requests.
You can do this with the IP HTTP Proxy feature, but be very careful not to allow it to proxy for anything that goes back out to the Internet, otherwise, your router will get discovered as an open proxy and hijacked by the forces of evil who will use it to either anonymize their activities or participate in DDoS activities.