What Im trying to do is easiest explained by some sample code

#!/usr/bin/perl -w
use strict;
use diagnostics;

my %hash;

%hash = ( 1 => { ONE       => "testdir",
                 TWO       => "tmpdir" },

          2 => { LOCATIONA => "$hash{1}{ONE}/$hash{1}{TWO}/my_file.txt
+",
                 LOCATIONB => "$hash{1}{TWO}/$hash{1}{ONE}/my_file.txt
+" } );

print "$hash{2}{LOCATIONA} = location a\n";
print "$hash{2}{LOCATIONB} = location b\n";
[download]

The output I get is this

Use of uninitialized value in concatenation (.) or string at test2 lin
+e 7 (#1)
    (W uninitialized) An undefined value was used as if it were alread
+y
    defined.  It was interpreted as a "" or a 0, but maybe it was a mi
+stake.
    To suppress this warning assign a defined value to your variables.

    To help you figure out what was undefined, perl tells you what ope
+ration
    you used the undefined value in.  Note, however, that perl optimiz
+es your
    program and the operation displayed in the warning may not necessa
+rily
    appear literally in your program.  For example, "that $foo" is
    usually optimized into "that " . $foo, and the warning will refer 
+to
    the concatenation (.) operator, even though there is no . in your
    program.

//my_file.txt = location a
//my_file.txt = location b
[download]

Is there a way to do this within a hash?