Feature request: process group id and session id

On Linux, I need to be able to tell if any process in a group (or session) is still alive. Unfortunately process_iter()'s Processes don't have this information.

This page says how to find the information on Linux; not sure about other platforms: http://unix.stackexchange.com/questions/132224/is-it-possible-to-get-process-group-id-from-proc