Not exactly. My CT is on the host A, and the host A, srv B is a external nfs server mounted via /etc/fstab at /ftp path.
In the CT, the mount point is enable through the config file /etc/pve/lxc/123.cfg like this :
mp0: /ftp,mp=/ftp
So my new server C will be update in the /etc/fstab on...