TYPO3 v6 has reached its end-of-life April 18th, 2017 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.
There is no further ELTS support. It is strongly recommended updating your project.
You can enter TSconfig for both backend users and groups. The resulting TSconfig for a certain backend user is the accumulated TSconfig for all the backend groups he is a member of. Thus you can override formerly set options from the user groups by entering another configuration in the TSconfig field of the user himself.