Matching users to each other - php

Question

How can I make that on clicking submit button, match the users to each other, like "Secret Santa" rules? You should not be Santa of yourself, and you should not be Santa of someone who is already your Santa. After that I'm gonna filter with user->groups (Tags shown on photo)
This is my .blade.php:
#extends('layouts.app')
#section('content')
<div class="container">
<div class="row justify-content-center">
<div class="col-md-8">
<div class="card">
<div class="card-header">{{ __('List') }}</div>
<div class="card-body">
<form action="">
#foreach($users as $user)
<div class="users-list" style="padding: 5px 0">
<h5>{{ $user->name }}</h5>
<p class="badge badge-primary">{{ $user->group }}</p>
</div>
#endforeach
<input class="btn btn-primary w-100" type="submit" value="Submit">
</form>
</div>
</div>
</div>
</div>
#endsection
And this is my RegisterController.php:
namespace App\Http\Controllers\Auth;
use App\Http\Controllers\Controller;
use App\User;
use Illuminate\Foundation\Auth\RegistersUsers;
use Illuminate\Support\Facades\Hash;
use Illuminate\Support\Facades\Validator;
class RegisterController extends Controller
{
/*
|--------------------------------------------------------------------------
| Register Controller
|--------------------------------------------------------------------------
|
| This controller handles the registration of new users as well as their
| validation and creation. By default this controller uses a trait to
| provide this functionality without requiring any additional code.
|
*/
use RegistersUsers;
/**
* Where to redirect users after registration.
*
* #var string
*/
protected $redirectTo = '/home';
/**
* Create a new controller instance.
*
* #return void
*/
public function __construct()
{
$this->middleware('guest');
}
/**
* Get a validator for an incoming registration request.
*
* #param array $data
* #return \Illuminate\Contracts\Validation\Validator
*/
protected function validator(array $data)
{
return Validator::make($data, [
'name' => ['required', 'string', 'max:255'],
'email' => ['required', 'string', 'email', 'max:255', 'unique:users'],
'password' => ['required', 'string', 'min:8', 'confirmed'],
]);
}
/**
* Create a new user instance after a valid registration.
*
* #param array $data
* #return \App\User
*/
protected function create(array $data)
{
return User::create([
'name' => $data['name'],
'email' => $data['email'],
'group' => $data['group'],
'wish' => $data['wish'],
'password' => Hash::make($data['password']),
]);
}
}