Use quota on multiple partitions/external storage

Good evening!

I'm using CWP for a while and it's working very good.
Now I had the idea to get more storage capacity from VPS provider.

The storage is being mounted as external storage. (/mnt/externalstorage)
I created symlinks to a backup directory in the folders of my users (/home/user1/backup - symlink to -> /mnt/externalstorage/user1/backup)

Is it possible to use the same quota on this external storage?

fstab:
/dev/mapper.....etc /home                   ext4    usrjquota=quota.user,jqfmt=vfsv0        1 2
/dev/vdb1 /mnt/externalstorage           xfs defaults 0 0

thank you very much!