Thread:Project:Support desk/how to enable user rights

We are using wiki intern as a knowledge base, no access by strangers. That works quiet good. But now we want to add an additional user account for a new member of our group, but not allow him to read all the pages we created until now AND will create in future. Just this new user can add his own content, which we can read and edit. From now on, the default settings shall be like this. When we add pages, it is not readable for him, until we decide the page to be accessable for him. How is this possible?