My tactics for dealing with groups are simple. I give the leader a healthy dose of intention and I react to nothing they do. I watch my body language to make sure I'm impossible to read and I just quietly wait for them to wet themselves.
People fear people they can't connect with and can't read...
I've found that I can use the same method to psychologically crush just about anyone only I've refined it so it works in a couple of minutes.
The nice thing about clear hierarchies is that the followers will usually do what the leader says and the leader will usually do what he or she can to keep the respect of the followers. With that kind of thing in mind, I think psychology is a great part of self-defense...maybe even central. Beware the "1%-er" though.