CC2640R2F: sdk 1.50.00.58 How to use whitelist

Hello, I would like to ask a question about how to use the CC2640R2F whitelist. The current problem is
If there are no devices nearby, the search works smoothly, 
but if there are many nearby devices, the namespace for the code below is not found in the list, making scanning impossible. To solve this problem, 
I would like to whitelist namesapce and search only namesapce like the code below. The namespace was created with the code below.

if(observer_mode==1){
 if(pEvent->deviceInfo.dataLen == 28){
 Util_stopClock(&uartReadClock);
 memcpy(rsp_data, pEvent->deviceInfo.pEvtData, pEvent->deviceInfo.dataLen);
 if((rsp_data[10]==0x53)&&(rsp_data[11]==0x61)&&(rsp_data[12]==0x6d)&&(rsp_data[13]==0x73)&&(rsp_data[14]==0x75)&&(rsp_data[15]==0x6e)&&(rsp_data[16]==0x67)&&(rsp_data[17]==0x45)&&
 (rsp_data[18]==0x64)&&(rsp_data[19]==0x64)){ // NameSpace
 
 //if(!RssiSendTimeFlag)
 {
 uart_printf("BUZON");
 //sprintf(rssi_data, "%d", pEvent->deviceInfo.rssi);
 //uart_printf("%s", rssi_data);
 //Util_startClock(&RssiClock);
 //RssiSendTimeFlag = 0;
 }
 }
 Util_startClock(&uartReadClock);
 }
 }