You can do this very easy and obvious with the following (from the previous examples) known trick. Lets say you want to keep your backup for 60 days and all files in the directory ``notimportant'' for only 7 days.
Simply make two backups, one with --keepAll 60d and exclude directory ``notimportant''. Make the second backup with --keepAll 7d for the missing directory. Like described in Example 3, create a relationship between the backups. So, if you move or copy a file between ``notimportant''' and the rest of your saved directories, you will not use additional space for the file.
Heinz-Josef Claes 2014-04-20