Default Sort for grouped table

I have a datatable that was created by a different developer. The table is using rowGrouping. It loads correctly, and after loading, can be resorted by the alphanumeric value in column 4, but I can't seem to find a way to get the default sorting for that column to be ascending. The default is however the table is built. I was hoping to alter the datatable default sort, rather than trying to change the way the table is built.

Here is how it is currently being created:

$('#people_block_holder table').dataTable({
            'bJQueryUI': true,
            'iDisplayLength': 50,
            'sPaginationType': 'full_numbers',
            'aoColumns': [
                {},
                {},
                {},
                {'sType': 'alphanumeric' },
                { 'sType': 'currency' },
                {}
            ]
        }).rowGrouping();
        $('select#actions').not('.dataTables_length select').not('.no-selectmenu').selectmenu();

I have tried adding 'order':[[4, 'asc']] and aaSorting, but nothing seems to change the default sort order.