Item Fulfillment sorted by Sales Order

I Have created a suitlet where we display all items under a sales order in a sublist. When I select 2 items from 1 sales order I get 2 item Fulfillment record.
This is what we dont want. It should be like for 1 salesorder there should be 1 item fulfillment irrespective of the no. of items selected under it.
My code is:
else
{
 
  iline = 0;
  var line = request.getLineItemCount('custpage_markall');
  for(i = 1; i <= line; i++)
  {
   var checkbxval = request.getLineItemValue('custpage_markall','custpage_itemful1', i);
   if (checkbxval == 'T')
  {
   var item1 = request.getLineItemValue('custpage_markall','custpage_itemful2', i);
   var salesorder1 = request.getLineItemValue('custpage_markall','custpage_itemful5', i);