title: Kendo UI filter on boolean
body: <p>Is it possible to have a filter menu with options such as Yes, No, Other</p>
  
  <p>I have a grid with a column which could have only 3 values Yes, No or Other. The filter should show radio buttons with these values and two button Filter and Clear. Is this possible?</p>
  
  <p>When I try with field type:"boolean", I get 'Yes' and 'No but how do I add the third radio button 'Other'.</p>
  
  <p>Any help would be appreciated.</p>
  
  <p>Thanks</p>