Selection
You can restrict the number of Buttons that can be selected by using the selection property of each Button within the ButtonGroup.
The property can be configured for a single or multiple selection.
<div id="buttongroup">
<span class="k-active">Option 1</span>
<span class="k-active">Option 2</span>
<span>Option 3</span>
</div>
<script>
$("#buttongroup").kendoButtonGroup({
selection: "multiple"
});
</script>