BCC is an email function, the SMS protocol has no such thing. It was never designed to be used to send a message to more than one receiver. (SMS is the protocol used by the old digital pocket pagers that could display a message when someone called your pager.) If you have to send a message that has to have a blind copy (that's what BCC is) sent, use email.
And, no, no one can design an SMS app to send BCC, since it wouldn't be SMS. It's like asking someone to design a feline dog. It would be a messaging app, using a messaging protocol that included provision for BCC, but it wouldn't be compatible with SMS. You'd need some server between that app and phones using SMS to translate between them.
Someone's done that once already - the company is Apple and the protocol is called iMessage. And it doesn't always work, unless you use the iMessage part as a strictly SMS-protocol app.