Multiple websites built on one Laravel framework?

I am doing something very similar. Here is how I am doing it:

Routes:

//this is for the main default domain that I host my main site/CMS
Route::group(['domain' => 'maindomainforcms.com'], function(){
    Route::get('/', function(){ return 'this is the index page'; });
});

//this catches the rest of the domains and all their pages:
Route::any('{all}', 'SitesPublicController@index')->where('all', '.*');

SitesPublicController.php

use App\Http\Middleware\VerifiedDomain;

class SitesPublicController extends Controller {

    public function __construct(){
        $this->middleware('domain.verify');
    }

    public function index(VerifiedDomain $verified_domain){
        $Site = $verified_domain->getSite();
        $Page = $Site->getPageByRequest();//This method gets the url segments then selects the proper page

        if(!$Page){ throw new NotFoundHttpException; }

        return $Page->content;
    }

}

VerifiedDomain.php middleware file:

use Closure;
use App\Domain;//this is just a model where I associate domains with sites
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

class VerifiedDomain {

    protected $Domain;

    public function handle($request, Closure $next){

        $domain = $_SERVER['SERVER_NAME'];
        $Domain = Domain::where('domain', $domain)->first();

        if(!$Domain){ throw new NotFoundHttpException; }

        $Site = $Domain->site;

        if(!$Site){
            throw new NotFoundHttpException;
        }

        $this->Domain = $Domain;

        return $next($request);
    }

    public function getDomain(){
        return $this->Domain;
    }

    public function getSite(){
        return $this->Domain->site;
    }

}

I also assign the VerifiedDomain Class as a singleton so I can use Dependency Injection on the Controllers. I hope this helps.

EDIT: I left this out: I added this to my http kernel file:

    protected $routeMiddleware = [
        //other stuff...
        'domain.verify' => 'App\Http\Middleware\VerifiedDomain',
    ];