Tape access sis strictly sequential. One file after another, but they are not different "files" on tape, they are one file in MTF (MicrosoftTapeFormat). Restore software reads the single big file and selects the data corresponding to one logical file based on "marks" in the bkf file
I'm not sure where you are trying to go here. You cannot delete only one "file" from a tape or insert a file. You can only delete the entire BackupSet or append to the end of it.
I am not trying to delete or append data to a tape. I am going to do a restore and have to be sure for our Security group that my file that I am restoring is not touching one of the confidential files.
The Department of Defense is involved in this and they are a little picky!
If they are that picky about which files may or may not "touch" each other or be "next to" each other on tape, create separate backup jobs to separate tapes for the "secure" data, so in future you don't have to satisfy some security weenie just to do a restore for a regular user.