Running two Volumio NAS

Not knowing much about networks, please excuse any foolish errors!

I run two copies of Volumio2. Each has been re-named (HiFi & Portable). Each has mounted the house NAS using it’s name (BTHUB…) and filepath/ share (USB4). All is fine.

I have also mounted each Volumio NAS on the other Volumio. (HiFi NAS onto Portable and visa versa. All is fine except that I have to use the address and “INTERNAL STORAGE” to mount them. As they are to be used in various locations I would really like to use the Volumio name rather than the address.

If, for example, the HiFi Volumio was the first to be booted, I can mount it onto the Portable Volumio by using “Volumio” and “INTERNAL STORAGE” but that only works for the first one booted.

Looking at the network each Volumio has a dchp name (hifi & portable). Each can be seen by AirPlay.

Have I missed a setting somewhere or an I asking too much?
Any help gratefully received (and very slowly digested!).