Block SMS without number

In India, we often receive SMSs which do not actually have a number, but instead, have a name like 'VK-AMSWAN'. SMS blockers like Truecaller don't have any facility to recognise such senders and keep asking for a number to block. When using third-party SMS apps like Chomp SMS, there is an option to show the contact number below the contact name. Guess what it shows for the spam? - VK-AMSWAN (name) - VKAMSWAN (where the number shows up for other contacts) How do I block such senders? I cannot blanket block all unknown SMSs because even banking information comes from such named senders. It seems SMS blocking isn't as well developed as call blocking is. Truecaller actually rejects spam calls without you ever knowing about them. No SMS blocker I've seen has this facility so far. All they do is receive the messages and hide them. If someone can locate a method to fully block spam SMS, please do tell. :)