I have one Windows server that runs multiple virtual servers (some Windows / some Linux) via Hyper-V. My ISP gives me a dynamic IP and blocks the use of ports 80 and 443 but all other ports maybe opened through the modem/router provided by the ISP. I want all of my virtual servers to be reachable via a custom domain and sub domain combination like https://MyWinSrvA.MyDomain.com to go to my Windows virtual server https://MyLinuxSrvA.MyDomain.com to go my Linux virtual server. All connections must be https. All servers are development servers that require public Internet access to demo my work. They are not production servers.

So what do I do?

use Web Redirect with the Port Forwarding option.

Home>Control Panel>Dynamic DNS Services>Manage Dynamic DNS Service>Manage Web Redirect

I do exactly the same as you and have many VM's runnning with web servers on non standard ports. SO people can access the sites with out remembering the port numbers, this is how I do it.