Repository copy with different policies

Hi all,
I currently have setup my first repository with Kopia using the local file system and I’m really satisfied with it!

I would now like to store a copy of my repository on my NAS as a safety measure, but with a stronger retention policy. I was thinking like having only the last few backups kept on my PC, while keeping 30 days on my NAS, or something like that.
I tried with the sync-to command, but I don’t get how to set different policies, it seems like an exact copy.
What would be the best way to proceed?