Remove duplicates in relation collection and count on pivot table data

I have three different tables/models: order, lamp and the pivot table lamp_order. Order and lamp have a many-to-many relationship. In the pivot table not only the IDs are stored but also the room where the lamp should be placed in. The pivot table looks like this:

| id  | lamp_id | order_id | room     |
| ----|-------- | -------- | -------- | 
| 1   | 1       | 1         | hall    | 
| 2   | 1       | 1         | hall    |
| 3   | 2       | 1         | hall    |
| 4   | 2       | 1         | kitchen |
| 5   | 2       | 1         | kitchen |
| 6   | 3       | 1         | kitchen |

When an order needs to be changed I want to be able to change the amount of the same lamp in the room it should be placed in. So I want to group the lamps per room and lamp_id, count those and remove the duplicates. An example of how the data should look like:

'id' => 1,
'name' => 'John Doe'
'email' => '[email protected]'
'notes' => 'Lorem ipsum dolor sit amet'
'created_at' => '2020-04-02 12:32:30' 
'updated_at' => '2020-04-02 12:32:30'
'lamps_count' => 6
'grouped_lamps' => [
  [
   'id' => 1
   'name' => 'Lamp 1'
   'fitting' => 'E14'
   'shape' => 'candle'
   'room' => 'hall'
   'count' => '2'
  ],
  [
   'id' => 2
   'name' => 'Lamp 2'
   'fitting' => 'E27'
   'shape' => 'pear'
   'room' => 'hall'
   'count' => '1'
  ],
  [
   'id' => 2
   'name' => 'Lamp 2'
   'fitting' => 'E27'
   'shape' => 'pear'
   'room' => 'kitchen'
   'count' => '2'
  ],
  [
   'id' => 3
   'name' => 'Lamp 3'
   'fitting' => 'E27'
   'shape' => 'stick'
   'room' => 'kitchen'
   'count' => '1'
  ],
];

I currently have this function in my controller, it isn't finished yet because it doesn't return the preferred data structure:

   $orders = Order::withCount('lamps')
            ->with('lamps.image')
            ->get()
            ->map(static function (Order $order) {
                $order->lamps->each(static function (Lamp $lamp) {
                    $lamp->room = $lamp['pivot']['room'];
                });

                return $order;
            })->each(function (Order $order) {
                $groupedLamps = $order->lamps->groupBy('room');
                $order->lamps->each(function (Lamp $lamp) use ($groupedLamps) {
                    $lamp->count = $groupedLamps[$lamp->room]->count();
                });
            });

        return response()->json([
            'orders' => $orders,
        ], 200);

I have a function in my order model to get the related lamps like this:

    public function lamps()
    {
        return $this->belongsToMany(Lamp::class, 'lamp_order', 'order_id', 'lamp_id')
            ->withPivot('room');
    }

The data it returns is almost right but the count of the lamps is not right because it counts the lamps per room what results in a data structure like this:

'id' => 1,
'name' => 'John Doe'
'email' => '[email protected]'
'notes' => 'Lorem ipsum dolor sit amet'
'created_at' => '2020-04-02 12:32:30' 
'updated_at' => '2020-04-02 12:32:30'
'lamps_count' => 6
'grouped_lamps' => [
  [
   'id' => 1
   'name' => 'Lamp 1'
   'fitting' => 'E14'
   'shape' => 'candle'
   'room' => 'hall'
   'count' => '3' // total amount of lamps for room hall
  ],
  [
   'id' => 1
   'name' => 'Lamp 1'
   'fitting' => 'E14'
   'shape' => 'candle'
   'room' => 'hall'
   'count' => '3' // total amount of lamps for room hall
  ],
  [
   'id' => 2
   'name' => 'Lamp 2'
   'fitting' => 'E27'
   'shape' => 'pear'
   'room' => 'hall'
   'count' => '3' // total amount of lamps for room hall
  ],
  [
   'id' => 2
   'name' => 'Lamp 2'
   'fitting' => 'E27'
   'shape' => 'pear'
   'room' => 'kitchen'
   'count' => '3' // total amount of lamps for room kitchen
  ],
  [
   'id' => 2
   'name' => 'Lamp 2'
   'fitting' => 'E27'
   'shape' => 'pear'
   'room' => 'kitchen'
   'count' => '3' // total amount of lamps for room kitchen
  ],
  [
   'id' => 3
   'name' => 'Lamp 3'
   'fitting' => 'E27'
   'shape' => 'stick'
   'room' => 'kitchen'
   'count' => '3' // total amount of lamps for room kitchen
  ],
];

I also want to remove the duplicates from the array like in the preferred data example I gave. Any help is appreciated, if you need anymore information or data then I am more than willing to help you. Thanks in advance.