How to add items in combobox2 by item selected in combobox1

Question

In XAML I have two ComboBoxes.If I select Item1 in ComboBox1 then some items should be added in ComboBox2.(i.e) ComboBox1 has Items such as Mango,Apple and Tiger On selecting Mango in the ComboBox1, item such as Fruit,Animal should be added to the ComboBox2 automatically.Can anyone suggest me XAML code for this.