GroupsApp.Role.OWNER

function myGroupsApp() {
  var email = Session.getActiveUser().getEmail();  
  var strDomain = email.split(/@/);
  var supportEmail = 'support@' + strDomain[1];
  var group = GroupsApp.getGroupByEmail(supportEmail);
  if (group.getRole(email) == GroupsApp.Role.OWNER) {
    Logger.log('These are the group owners ');
  }
}