It was years ago, so my memory might not be perfect, but I had something that kinda did that. I think it was an Xposed module called GravityBox, and there was an option to limit repeat notifications. I had set a cool down period of probably 1 minute, meaning if I received multiple messages within 60 seconds, it would only notify once, but if I received another message 60+ seconds after the first, it would ding again. I'm pretty sure that the cool down period was customizable per app too. Damn, I miss that.