ability to isolate groups of containers from one another

would be nice to provide sets of containers name, and pumba would isolate one set of containers from the other set (affect traffic between the two sets, but not affect other traffic)

i wrote the code to do this in my app
(https://github.com/grafana/metrictank/blob/1003db861aa5943d70b481f07cabbdff735967f8/stacktest/docker/docker.go#L65-L118 ) quite a while ago
