Change value of data in my KendoGrid filter

Question

I want to change the value of the data on my filter. Using the example code provided by telerik, i want to use a short country´s name (substring) on my filter, so i can use USA, CAN, MEX or else. Some ideas?

<div id="grid"></div>
<script>
    $("#grid").kendoGrid({
        columns: [ {
            field: "country",
            filterable: {
                multi:true,
                itemTemplate: function(e) {
                    return "<span><label><span>#= data.country|| data.all #</span><input type='checkbox' name='" + e.field + "' value='#= data.country#'/></label></span>"
                }
            }
        }],
        filterable: true,
        dataSource: [ { country: "CANADA" }, { country: "USA" }, { country: "MEXICO" } ]
    });
</script>