May be if all files of same extensions, you can create directive to skip extensions or if files are under one folder tree, you can skip the entire folder.

No, I don't think you can do this.

Well the problem is I want to backup the stub files left by disxtender after the files have been archived to Centera, and the stub files, so there is nothing I can do as far as grouping then as polices set when files are archived.

There is no means to do that, in fact if there were it would cause mass customer confusion. The stub is just a pointer to the file after it has been archived to centera so when the customer goes to access it, it can be recalled. If the file were to change the customer would not recognize it or assume it has been deleted via a source scan or orphan policy. Thanks for your help though it has been appreciated and answered my question.

I don't know much about DiskXtender but are the stub files not of the same extension or created in the same folder.

May be DiskXtender has some means to customize the location of stub files.