Amazon S3 just folder rights

Hey guys, i look at your help and faq section but i cant find any solution for my problem.
I use, and LOVE, your plugin. I backup to amazon s3 and all works great. The only thing i cant getting to work is one bucket for several users while a user just can work, list and see his own subdir.
I dont wanna use own buckets for every website.
For now its like:
updraftbackup/website1/*
updraftbackup/website2/*
updraftbackup/website3/*
With your post from 2013 and some help by aws help sites i can handle that every user can write and delete only in his subfolder but still can list all other buckets and dirs.
Do you have an HowTo or perhaps an template how i can solve this?
best regards
Dennis