Main
  Name = Countries
End

Sub
  Action = Find: NA
  Text = North America
End

Sub
  Action = Find: EU
  Text = Europe
End
---
Main
  Name = NA
End

Sub
  Action = Find: US
  Text = United States
End

Sub
  Action = Find: CA
  Text = Canada
End

Sub
  Action = Find: MX
  Text = Mexico
End
---
Main
  Name = US
End

Sub
  Action = 
  Text = Boston
End

Sub
  Action = 
  Text = Atlanta
End
---
Main
  Name = EU
End

Sub
  Action = 
  Text = France
End

etc...

##</code><code>##

%ref_list = ( 'Countries' => { 
		'North America' => {
			'United States' => {
				'Boston' => undef,
				'Atlanta' => undef
				},
			'Canada' => undef,
			'Mexico' => undef
			}
		'Europe' => {
                       'France' => undef
                       }
		},
	      );