Most of them most likely work by themselves. It has been the way for at least two thousand years. Mine seeks out others and works in groups. I will rebuild in a few years as for now we educate. No Secrets just facts and help.
Secrets are oral things.
Each coven will find and make there own secrets over time you see. This is done by a base of teachings. As for Now I am The only Child Of Morrigan in my group. In the Future the other children will come. As for now I am not ready yet being I am still learning always myself.