Как правильно добавить groupBy в запрос?

select `characteristics`.*
from `characteristics` 
inner join `category_characteristic` on `characteristics`.`id` = `category_characteristic`.`characteristic_id` 
where `category_characteristic`.`category_id` in (51, 52) 
group by `characteristics`.`id`

select `characteristics`.*, `category_characteristic`.`category_id` as `pivot_category_id`, `category_characteristic`.`characteristic_id` as `pivot_characteristic_id`

/* Получает характеристики категории */
public function characteristics()
{
   return $this->belongsToMany('App\Models\Admin\Characteristic');
}

Schema::create('category_characteristic', function (Blueprint $table) {
            $table->increments('id');
            $table->unsignedMediumInteger('category_id');
            $table->unsignedMediumInteger('characteristic_id');
            $table->foreign('category_id')->references('id')->on('categories');
            $table->foreign('characteristic_id')->references('id')->on('characteristics')->onDelete('cascade');
        });

$categories = Category::whereIn('id',$request->input('categories'))->with(['characteristics' => function($query) {
            $query->groupBy('characteristics.id');
        }])->get();