$(document).on("change", '[id$=ddlPayToIndividual]', function () {
    . . . // unrelated code elided for brevity
    var $uscitizenyes = $('[id$=rbUSCitizenOrPermResY]');
    var $uscitizenno = $('[id$=rbUSCitizenOrPermResN]');
    if (!$uscitizenyes.checked && !$uscitizenno.checked) {
        alert('You must select above whether payee is a US Citizen or Permanent Resident or not');
    }
});