You can serve on multiple domains using a reverse proxy server, like nginx.
Check out this question here: Nginx Different Domains on Same IP
But the basic idea is one server actually listens on port 80, and it handles sending the request to the right app server (php, node, etc) on your machine serving internally (localhost:8000).
It's not technically very hard to do, but getting used to configuring a new piece of software like nginx can be a little challenging. Definitely definitely doable though!