Still no answer.
I didn't answer this yesterday, because I'm not a Legato user. The question would be, why do you want to do that? In all the different backup software I've used, I try to stick to the tools provided by that software. So, if you're running out of disk space, for example, you might have a specific command to tell the software to forget some of the older backups. That would remove indexes. Some software has utilities as well to regenerate indexes by scanning the backup media. If you screw up by manually deleting things, or it just gets corrupted somehow, some of them have a repair utility.
So, if you can answer the "why", and look through the native Legato utilities, then maybe there will be a better answer. Or switch to open source
, and then you would probably have more people jumping in here with answers.