There are a few ways I can think of to do this but I’m not sure what would be the best way.
You can just mount individual drives or partitions to the corresponding location (xdg directories or otherwise). This is what I generally do.
I haven’t tried this but If you don’t want to partition the shared drives, you could make corresponding folders on the root of the drive (or anywhere really) and bind mount those folders to the corresponding location. For it to be persistent across reboots, a brief search says you can put it in fstab this way: /source /destination none defaults,bind 0 0 There is also rbind which I think is recursive but I haven’t read up on when to use it.
I haven’t tried this either and forget which is which but symbolic link or hard link may or may not be viable and would also be persistent I think.