author not changed

i have a little problem here.

I have made a default blog with content in the pages. When new users register they get the webpages with the content. But the problem is, the author of the pages of the new user is the author of the default blog.
And i dont whant this because i have shotcuts that imports data with author id.

Manual solution is to go to the new user "pages" and than "author" and than change the author. The shortcuts are than correct. But i dont want this, its too much when i have to many users.