multiple hosts with same hostname but different fqdn

Hello everyone

This may be a very basic question or simply impossible. Either way I have not been able to find any information in the documentation about this.
I have two instances I’d like FAI to install for me:
interhost5.de.mynet.work
and
interhost5.us.mynet.work

Unfortunately I don’t know how. So far I have never had two hosts with the same name but different DNS tags / FQDNs but now I do.
How do I do this right? In the “50-host-classes” I have so far always only put the hostname without domain and it does not seem to be working with the FQDN (as makes sense with the expression `case $HOSTNAME in`. Is there a way around that? Any suggestion (as clean as possible 😊 ) is highly welcomed.

Thanks and cheers
Tobi