how can i bind a label in a third page to receive data from page one and two

i am new to Xamarin. in the app that a developing, the main-page contains three buttons that navigate to three popup pages. page one and two both contain a picker and the third page a label. i would like to know how can i bind the label in the third page to receive data from both page one and two depending on the page the user selected a value? so if the user navigate to page 1 and selects a value from the picker, the label should only display the value from page 1, same way if the user select a value from page 2 this same label should only display what was selected in page 2. it should always display one data value.
i hope its understandable.
thank you in advance

First page

<StackLayout>
        <Label Text="Laterality:" TextColor="Black"  FontSize="Default" ></Label>
        <Picker SelectedItem="{Binding PICKER1}" WidthRequest="120" FontSize="10" TextColor="Black" VerticalOptions="Center" BackgroundColor="WhiteSmoke">
            <Picker.Items>
                <x:String>15 cm</x:String>
                <x:String>30 cm</x:String>
                <x:String>45 cm</x:String>
                <x:String>60 cm</x:String>
                <x:String>75 cm</x:String>
                <x:String>90 cm</x:String>
            </Picker.Items>
        </Picker>

On the second page i have this

<StackLayout BackgroundColor="White">
        <Label Text="orientation:" TextColor="Black"  FontSize="Default" ></Label>
        <Picker SelectedItem="{Binding PICKER2}" WidthRequest="120" FontSize="10" VerticalOptions="Center" BackgroundColor="WhiteSmoke">
            <Picker.Items>
                <x:String>Vertical</x:String>
                <x:String>horizontal</x:String>
            </Picker.Items>
        </Picker> 

lastly on my last page i have a label which is suppose retrieve the values from the fist and second page depending on which page i did something on. so if the user selects something on page 1, the label should only display what is selected from page 1 and and viceversa.

        <Label Text="{Binding DisplayPICKER1}" Margin="5"  HorizontalOptions="StartAndExpand"  VerticalOptions="CenterAndExpand"></Label>

This is the MainViewModel. currently with this MainViewModel i need 2 labels, but i would like to use just one label

  string picker1 = string.Empty;
    public string PICKER1
    {
        get => picker1;
        set
        {
            if (picker1 == value)
                return;
            else
            {
                picker1 = value;
                OnPropertyChanged(nameof(PICKER1));
                OnPropertyChanged(nameof(DisplayPICKER1));
            }
        }
    }
    public string DisplayPICKER1 => $"laterality:{PICKER1}";


  string picker2 = string.Empty;
    public string PICKER2
    {
        get => picker2;
        set
        {
            if (picker2 == value)
                return;
            else
            {
                picker2 = value;
                OnPropertyChanged(nameof(PICKER2));
                OnPropertyChanged(nameof(DisplayPICKER2));
            }
        }
    }
    public string DisplayPICKER2 => $"Orientation:{PICKER2}";

baseview

public class baseview : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    public void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}