How to judge whether a short message is a group short message?

It can be judged that there are three types of SMS group sending, one is issuing cards, the display number is a virtual mobile phone number, and the callback number is empty or prompting other abnormal use number information; The other two are easy to judge. One is the mobile gateway, and the first three digits of the display number must be 106. The last one is the telecom gateway, and the first few digits of the display number are generally the area code where the gateway is located.