can anyone point me towards the correct usage of grouping with a filterExpression?

psuedoLogic: I want to grab the status of several work orders related to the line items on a sales order

currently I have

   var lineCount = record.getLineItemCount('item');    var lineData = [];    for (var i = 1; i <= lineCount; i++) {     woid = record.getLineItemValue('item', 'woid', i);     if (woid !== null) {      lineData.push({lineid: i, woid: woid});      //filters.push(new nlobjSearchFilter('internalid', null, 'is', woid));      filters.push(['internalid', 'is', woid]);      filters.push('or');     }    }    filters.pop();        var columns = [        new nlobjSearchColumn('tranid'),        new nlobjSearchColumn('internalid'),        new nlobjSearchColumn('statusref'),    ];        var results = nlapiSearchRecord('workorder', null, filters, columns);