What exactly are you trying to do? Knowing the tables probably won't allow you to accomplish what you are looking for.
You can find the groups in the Containers table and the definition of the children in the ContainerMemberDefinition table.
I am trying to achieve the following:
When a whole geographical site goes down, I want to send and alert saying the site is down and the list of affected devices (its easy when its a whole site) but what can I do when its only a branch on a sites map?