I sent out a massive group text when I got my phone to inform everyone of my new number, but the responses came back in their own threads.
It's not something I would utilize very often, so I'm not too concerned about finding an app to do it. I'm pretty happy with the stock Messaging app aside from this.
Samsung Galaxy Note 8.0 N5110 Stock 4.2.2 rooted
Rogers HTC One
HP Touchpad with CM10