All Telerik .NET tools and Kendo UI JavaScript components in one package. Now enhanced with:
Please see the StackOverflow post here:
http://stackoverflow.com/questions/37794073/filtering-a-combobox-with-a-groupstyle
I found this example in a related question. This will work perfectly.
http://www.telerik.com/forums/editable-radcombobox-with-radtreeview