Using SBP to archive daily to monthly, quarterly and yearly

[dchaps]

I'm sure someone must have done this and I think it's easier and better managed in SBP than using scheduled tasks:
I backup some database files (about 10) each night and at the moment am keeping them "forever" on the destination server which is starting to take too much space.
I can easily delete any files more than 7 days old which almost does what I want - I would still have the 7 copies - but it's possible I might have an issue that I don't spot in 7 days, so, really, what I want to do is also keep one of those for a month, one for a quarter and one for a year.
Now ideally that yearly file would be exactly a year old but for that to happen I realize I would need to keep every daily copy for a year so there needs to be some compromise.
I want to keep as few copies as possible so I'm thinking a system of "buckets"
Every 7 days move a copy into a monthly bucket.
Every month move a copy from the monthly bucket to the quarterly bucket
Every quarter move a copy from the quarterly bucket to the yearly bucket.
Doing it this way I have fewer copies stored but my yearly backup is also always between 9 and 12 months old - which is good enough.
Does this make sense and has anyone found an efficient solution to this ?
Thanks,
David