Knockout JS - Cascading dropdown in the table (Grid)

Question

I am trying to implement a scenario of cascading dropdown with MVC3 & Knockout JS.

Example Scenario: below is the html table has 2nd and 3rd columns as dropdowns, want to implement it in cascading style, like column-dropdown should be populated based on the Table-Dropdown selection.

ColumnName       Table-DropDown    Column-DropDown      DefaultValue
Test1             Table1             Table1-Columns      ‘’
Test2             Table2             Table2-Columns      ‘’

Got an example http://knockoutjs.com/examples/cartEditor.html But could not get the complete code with all JSON data, so not able to figure out how exactly to implement this, help on this really appreciated.