You asked this question in the Battleship GB thread and I gave you an answer (for what it was worth) and a link to a similar question asked by someone else with the corresponding answers by others.
I'll reiterate. No, there isn't a Group Build FAQ but there should be. That link will give you mucho good info on what a GB is.
Also, simply reading the front page of each GB will tell you a lot about them.
Good luck, and