byte[] myByte = {"HelloOne", "HelloTwo", "HelloThree", "HelloFour"};
WriteAsync(myByte);

if (Bluetooth.available())
{
 while (true)
 {
   delay (50);
   char c = Bluetooth.read();
   readString += c;

   if (readString.length() >0) {

    if (readString[0] == "HelloOne")
    {
       Serial.println ("Hello One has been sent!");
    }

    if (readString[1] == "HelloTwo")
    {
       Serial.println ("Hello Two has been sent!");
    }

    if (readString[2] == "HelloThree")
    {
       Serial.println ("Hello Three has been sent!");
    }

    if (readString[3] == "HelloFour")
    {
       Serial.println ("Hello Four has been sent!");
    }

   }

 }

}