Transfer statistics per process or destination, not interface I would like to log upload statistics for an application I run on my Mac. 

Now, I know that with netstat -ib I can access statistics per network interface.
I also know that with lsof -i I can get a list of which connections each of the processes is maintaining. And finally I know that with iftop I can monitor in real time how much is flowing between my machine and a remote address. But none of this achieves what I am looking for. 

I am looking to get columns similar to the Ibytes and Obytes columns I get from netstat -ib, but get those for a specific remote network address OR for a specific local process ID.
Best I've been able to come up with myself is to write a script that runs iftop -f "dst net REMOTE_IP" -t in the background, redirecting the output, and after a certain timeout kills the process, and then grep/awk my way through the redirected output. Hardly elegant.