How to filtered two models with unrelated fields DART?

I have two models but they don't have the common id field, but i need to filtered all items. I am using where method and as I have read in docs that this methos can help resolve my issue. But the thing is that it works only with the same id fiels in both models. What can i do if i want to filtered by uncommon fields?

I saw the solitions where other people create the helper class for both models and merge them into one array, but the thing is it should has the predifined size of two arrays, if i will try to add another item in CoffeeShop models or another item in menu it gives an error about the length of arrays.

My models:

class CoffeeShop {
  CoffeeShop({this.shopTitle, this.id});
   int id;
  final String shopTitle;

  @override
  String toString() => "CoffeeShop(shopTitle: $shopTitle)";
}

class CoffeeShopMenu {
  int sid;
  final String store;
  CoffeeShopMenu({this.shopMenuTitle, this.store, this.sid});

  final String shopMenuTitle;

  @override
  String toString() => "CoffeeShopMenu(shopMenuTitle: $shopMenuTitle)";
}

The code of the first screen:

class _ExpState extends State<Exp> {
  final List<CoffeeShop> coffeeShop = <CoffeeShop>[
    CoffeeShop(id: 1, shopTitle: 'Strarbucks'),
    CoffeeShop(id: 2,shopTitle: 'Dunkin doghnuts'),
    CoffeeShop(id: 3,shopTitle: 'Subway'),
    CoffeeShop(id: 4,shopTitle: 'MCCafe'),
    CoffeeShop(id: 5,shopTitle: 'Coffee Shop'),
  ];


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        actions: [
          IconButton(
            icon: Icon(
              Icons.search,
              color: Colors.white,
            ),
          ),
        ],
      ),
      body: ListView.builder(
          itemCount: coffeeShop.length,
          itemBuilder: (context, index) {
            return ListTile(
              title: Text(coffeeShop[index].shopTitle),
              onTap: () {
                Navigator.push(
                    context,
                    MaterialPageRoute(
                        builder: (context) => Exp1(
                          //here i want item to be filtered
                            sid: coffeeShop[index].id,
                            shopTitle: coffeeShop[index].shopTitle
                            )));
              },
            );
          }),
    );
  }

}

The code of the second screen:

class _Exp1State extends State<Exp1> {
 final List<CoffeeShop> coffeeShop = <CoffeeShop>[
    CoffeeShop(id: 1, shopTitle: 'Strarbucks'),
    CoffeeShop(id: 2,shopTitle: 'Dunkin doghnuts'),
    CoffeeShop(id: 3,shopTitle: 'Subway'),
    CoffeeShop(id: 4,shopTitle: 'MCCafe'),
    CoffeeShop(id: 5,shopTitle: 'Coffee Shop'),

  ];

  final List<CoffeeShopMenu> coffeeMenu = <CoffeeShopMenu>[

    CoffeeShopMenu(sid: 1, shopMenuTitle: 'Matcha'),
    CoffeeShopMenu(sid: 1,shopMenuTitle: 'Matcha'),
    CoffeeShopMenu(sid: 4,shopMenuTitle: 'Matcha'),
    CoffeeShopMenu(sid: 4,shopMenuTitle: 'pie'),
    CoffeeShopMenu(sid: 3,shopMenuTitle: 'sandwich'),
    CoffeeShopMenu(sid: 4,shopMenuTitle: 'croissant'),
    CoffeeShopMenu(sid: 5,shopMenuTitle: 'croissant A'),
    CoffeeShopMenu(sid: 5,shopMenuTitle: 'croissant A'),
    CoffeeShopMenu(sid: 2,shopMenuTitle: 'croissant'),
    CoffeeShopMenu(sid: 2,shopMenuTitle: 'Latte'),
    CoffeeShopMenu(sid: 4,shopMenuTitle: 'Latte'),
    CoffeeShopMenu(sid: 3,shopMenuTitle: 'Latte'),
    CoffeeShopMenu(sid: 5,shopMenuTitle: 'Latte'),
  ];


 int index;
     List<CoffeeShopMenu> get coffeeMenuTitle => coffeeMenu.where((element) => element.sid == coffeeShop[index].id).toList();
 @override
 Widget build(BuildContext context) {

   return Scaffold(
     appBar: AppBar(),
     body: ListView.builder(itemCount: coffeeMenuTitle.length,itemBuilder: (context, index){

       return ListTile(
         title: Text(coffeeMenuTitle[index].shopMenuTitle),
       );
     }),
   );
  }
}