Yes, it’s possible. Since Apache is already installed the problem is two web servers trying to share the same ports 80 and 443.
There are different ways to resolve this problem. You could install Nginx and have it listen for two domains, and if it gets a request for the existing domain it acts as a reverse proxy in front of the Apache install and sends the request to Apache. You could change the port Apache listens on to 8000, for example.
All traffic goes through Nginx in this arrangement. It’s common. Apache would act as a backend service and not public facing.