In this case, I STRONGLY RECOMMEND that a feature of the sort be implemented in future releases of Toast. I am certain that it is not very complicated, as far as software is concerned at least, to program a record on how were spanned the different files among the disks.
But in my case, I cannot look at the files and the disks to know which ones have been written or not to media. The files I am backuping are of video type, sometimes larger thant the capacity of the disks (25GB Blu-Ray). Hence the fact that the software HAS TO SPLIT them up in smaller pieces, rendering it impossible for humans to know exactly where they were cut, let alone how they were spanned among disks. Only software can figure this out.