I try with "file to tape", but it seems it works in incremental mode, it replace the files when I save another year.
To make it always run a full cycle, just disable incremental processing for it.
The result I want : a tape for year 2014 for all servers. If the is 40% full, then I write on the same tape the year 2013 for all the servers... When the tape is full, I take another tape to write 2012, 2011, ...
In order not to overfill tapes with million individual files it might be worth backing up VMs containing restored data first, and then archive resulting backup file to tape.
Also, it might be a good idea to snapshot the source VMs first, restore data from 2014 to them from tapes written by 3-party solution, backup those VMs and transfer resulting backup files to mediums, using VB&R, then revert snapshot, restore 2013 dataset, backup, archive to tapes, etc.