How do dynamically get the hostname of another machine in hiera?

Question

I have a few machines, one of those has the class dbserver assigned via ENC. The other machines run software which need the DB. Now I want to configure this software to be able to connect to the DB. I usually prefer to use the hiera autolookup feature for this. So the software-class, let's call it foo, has a parameter $dbserver. This gets looked up in hiera as foo::dbserver. I can put a hiera lookup in hiera, like

dbserver:      foo.bar.example.com
foo::dbserver: "%hiera('::dbserver')"

So I only have to configure the hostname once in hiera. Plus I have to configure the dbserver-assignment in ENC. And I have to take care, that they match, so that the dbserver runs on the machine of which I put the hostname into hiera.

Is there a way to automate this? Can I tell hiera to somehow check on which server this class runs and use the hostname of that machine for configuration?

edit1: hiera.yaml

---
:backends: yaml
:yaml:
  :datadir: /etc/puppet/hieradata/%{::environment}
:hierarchy:
  - "nodes/%{::certname}"
  - "clients/%{::client}"    # custom fact
  - "os_%{::osfamily}"
  - common                   # the code above is inside this common.yaml