While I have been setting up an array of web servers to host various websites over the years, this little trick has definetly saved a lot of resources on my new setup.
It’s an IIS Web Application called “URL Rewrite”.
I personally set up a separate ‘site’ in IIS which will allow you to set up “subdomains” or “additional domains” and ‘bindings’ for each website that you host.
Instead of re-inventing the wheel so to speak, if you visit the website host below by Scott Forsyth that will step you through the instructions to get it setup.
The relevant links which I used to put together this guide are;https://weblogs.asp.net/owscott/iis-url-rewrite-hosting-multiple-domains-under-one-site