hostname variable in attachment replacement

[Erik Bloodaxe]

Is there a way to have a variable in the attachements that replace 
unacceptable file types and content that expands to the host names.

I.e. in stored.filename.message.txt in etc/reports/en

I want a line saying

File is in: $(HOSTNAME) in $quarantinedir/$datenumber/$id

so that my sysadmins can see which of the many servers the file is on as 
the standard reports give them no indication of which server to get the 
file from.

I have tried all the obvious

Regards

Erik