How can  we show  lookup functionality with custom FK relation instead of  database table relation ?

it’s running based on Foreign key based on db right now but we need to manage FK  relation by administrator(backend settings).

After debug some code , i found

 jQuery.fancybox.open({
         href: “#”+dataid,
            afterClose: function() {
             // jQuery(“#i5cul_erd_location_lookup_grid_i5cul_erd__BeId .ui-jqgrid-bdiv tbody tr”).unbind(“click”);
            }
          });

it’s showing icon for not loading lookup grid after removal  FK relation of table while we had need to manage for custom relation from admin manageable.

So can you guide me , how we can do it?