Flutter - Parse Json with parent set - json

Question

I can parse in my code json file like below. It works fine:
[
{
"albumId": 1,
"id": 1,
"title": "Accusamus beatae ad facilis cum similique qui sunt",
"url": "https://via.placeholder.com/600/92c952",
"thumbnailUrl": "https://via.placeholder.com/150/92c952",
"publishDate": "2021-03-12"
},
{
"albumId": 1,
"id": 2,
"title": "Reprehenderit est deserunt velit ipsam",
"url": "https://via.placeholder.com/600/771796",
"thumbnailUrl": "https://via.placeholder.com/150/771796",
"publishDate": "2021-03-12"
}
]
but i need to update my json file to be able to present data from a specific parent. In this example: position1 or position 2.
{
"position1":[
{
"albumId": 1,
"id": 1,
"title": "Accusamus beatae ad facilis cum similique qui sunt",
"url": "https://via.placeholder.com/600/92c952",
"thumbnailUrl": "https://via.placeholder.com/150/92c952",
"publishDate": "2021-03-12"
},
{
"albumId": 1,
"id": 2,
"title": "Reprehenderit est deserunt velit ipsam",
"url": "https://via.placeholder.com/600/771796",
"thumbnailUrl": "https://via.placeholder.com/150/771796",
"publishDate": "2021-03-12"
}
],
"position2":[
{
"albumId": 1,
"id": 1,
"title": "Accusamus beatae ad facilis cum similique qui sunt",
"url": "https://via.placeholder.com/600/92c952",
"thumbnailUrl": "https://via.placeholder.com/150/92c952",
"publishDate": "2021-03-12"
},
{
"albumId": 1,
"id": 2,
"title": "Reprehenderit est deserunt velit ipsam",
"url": "https://via.placeholder.com/600/771796",
"thumbnailUrl": "https://via.placeholder.com/150/771796",
"publishDate": "2021-03-12"
}
]
}
My code looks like below. What should I do to list only children items from ex: position1.
Future<List<Photo>> fetchPhotos(http.Client client) async {
final response = await client
.get(Uri.parse('https://jsonplaceholder.typicode.com/photos'));
return compute(parsePhotos, response.body);
}
// A function that converts a response body into a List<Photo>.
List<Photo> parsePhotos(String responseBody) {
final parsed = jsonDecode(responseBody).cast<Map<String, dynamic>>();
return parsed.map<Photo>((json) => Photo.fromJson(json)).toList();
}
and
body: FutureBuilder<List<Photo>>(
future: fetchPhotos(http.Client()),
builder: (context, snapshot) {
if (snapshot.hasError) print(snapshot.error);
return snapshot.hasData
? PhotosList(photos: snapshot.data!)
: Center(child: CircularProgressIndicator());
},
),