There are use cases where it would be really useful to quickly filter hosts discovered from prototypes by their parent hosts.
In addition, an optional field for hosts (in monitoring - hosts or configuration - hosts) where the parent host name would be displayed could also provide additional much needed information about hosts created from prototypes.

Another workaround would be the ability to develop a new macro and populate the host prototype host name with it. This macro would then get resolved as the parent host name.