One team, one price, unlimited users

I'm building out an application with Spark. The billing structure should be that the Owner pays a flat rate per month and then can send as many invitations as necessary. Invited users register and are not charged.

However, when my invited users follow the email link to register they are required to select a plan and pay.

My code looks like this:

SparkServiceProvider.php

 public function booted()
    {
        Spark::useStripe();

        Spark::freeTeamPlan()
            ->archived()
            ->features([
                'EHR', 'Document Upload', 'Beer'
            ]);

        if($_ENV['APP_ENV'] == 'production') {
          $this->registerMemberPlans();
        } else {
          $this->registerDevelopmentPlans();
        }



      Spark::identifyTeamsByPath();
      Spark::noAdditionalTeams();
    }

    public function register()
    {
        Spark::prefixTeamsAs('practices');
    }

// This function registers all my plans, there are about 10 plans but they all look the same they just have different prices.

 private function registerMemberPlans() {

      //
      Spark::teamPlan('POCA Member 25', 'plan_CuUgcLU1yfPsVk')
          ->price(25)
          ->features([
              'Feature 1', "Feature 2', 'Feature 3'
          ]);

        //...
}

How can I get rid of the plan selection and credit card charge for invited users users?