I just wanted to share an elegant solution I found for passing the group value to a button that handles picking the entire group:
"Group: #= value #, Count: #= count # <div data-val='#= value #' class='button black' onclick='GridPickGroup(this)'>Select Group</div>";
"Group: #= value #, Count: #= count # <div data-val='#= value #' class='button black' onclick='GridPickGroup(this)'>Select Group</div>";
function GridPickGroup(button) {
var value = $(button).data("val");
var currentGroupRow = $(button).closest(".k-grouping-row");
GridData.grid.select(currentGroupRow.nextUntil(".k-grouping-row"));
}