Multiple sites on one install

I’m looking to move 5 sites from WP to Grav. I would love to have these in one Grav install even though they have nothing to do with each other more than same writers and admins. And also move more sites into the same installation in the future.

I got the server set up with Grav working but noticed that the guide for multisite is made for subdomains and not seperate domains/sites.

Can someone supply me with a setup.php that instead supports completely different domains?