Display on select field for a summary search

I have a script that works fine, except when I want to display the partners name. It is a grouped saved search and works fine as partner_group, but the field partner_group_display does not work:
portlet.setTitle("Commission Detail List")
    var col = portlet.addColumn('partner_group_display','text', 'Agency', 'LEFT');
    col.setURL(nlapiResolveURL('RECORD','partner'));
    col.addParamToURL('id','partner_group', true);
    portlet.addColumn('custbody_target_group','integer', 'Target', 'LEFT');
  
    }



var sr = nlapiSearchRecord('transaction','customsearch_litres_result',null,null);
for(var i = 0;i< sr.length;i++){
sra = sr[i]
partnerCom[partnerCom.length] = new partnerResults()
partnerCom[partnerCom.length-1].partner_group = sra.getValue('partner_group')