How to create binding based off Session value?

I'm trying to bind an object based on a variable in the session. I'm basically trying to implement the strategy design pattern by binding the concrete class based on that session variable. Originally, I was doing it in the AppServiceProvider, something like this (just an example):

    public function register()
    {
        $this->app->bind('App\Services\CompanyServiceAbstract', function($app)
        {
            $userType = Session::get('userType');

            switch ( $userType )
            {
                case UserType::MANAGER :
                        return $app->make('App\Services\CompanyServiceConcrete');
                case UserType::USER :
                        return $app->make('App\Services\AnotherCompanyServiceConcrete');
            }
        });
    }

But I know that the session isn't available there, as I've read Taylor's response somewhere about the absence of an HTTP request. So my question is, how should I accomplish something like this otherwise?

Also on that note for future reference, if I didn't need the session variable, is what I did above acceptable? The reason I used $app->make() was because the class would require dependencies in the constructor() method.

Any feedback would be greatly appreciated. Thanks!