How to add Multiple models in collection ?

I have 3 different collection

public class Sample1

{

public int Id1 { get; set; }

public string Name1 { get; set; }

public bool Ischecked1 { get; set; }

}

public class Sample2

{

public int Id2 { get; set; }

public string Name2 { get; set; }

public bool Ischecked2 { get; set; }

}

public class Sample

{

public int Id { get; set; }

public string Name { get; set; }

public bool Ischecked { get; set; }

}

ObservableCollection SampleData = new ObservableCollection();

ObservableCollection SampleData1 = new ObservableCollection();

ObservableCollection SampleData2 = new ObservableCollection();

Add these ObservableCollection into 1 collection.

Thanks in advance ...