$ ps xf -o "%p %r %c %a" | grep 1234567 | grep sleep
11966 11833 sh sleep 1234567
11976 11833 sh sleep 1234567
11986 11833 sh sleep 1234567
11996 11833 sh sleep 1234567
12106 11833 sh sleep 1234567
$ ps xf -o "%p %r %c %a" | grep 1234567 | grep sleep | tail -1 | awk '{print $2}' | xargs -Igid kill -- -gid
Note: The double dash is needed here for xargs + kill -gid