[logback-user] How to use markers with hierachy?

Hi, I would like to know how it is possible to use marker using some hierarchy. Let me explain. I would like to have a marker like ROOT and a child marker like DB and this marker having 2 children BD_READ and DB_WRITE. Then in the configuration file, I would like to be able to disable all DB and children but letting all other children of the ROOT marker being logged. How should this be done in the code in a multiple web application environment? Thanks, Xavier.