Take a look at this forum post. It doesn't do exactly what you're asking for but it might help you manipulate the filter dialog to do what you need.
The important part is pasted below. You attach it to your grid's load event and mess with the filter dialog. This example changes the default filter to 'contains' instead of 'is equal to' but you could also do other things as long as you send the correct filter values in the end. This example is for the Telerik MVC extensions but replacing "t-" with "k-" in the class names should give you the desired result.
container = $(