I have a record of a certain number of fields, I know the fields, but I only know the field values in the code; the total set of values for each field is unknown

The way I had originally planned was a large hash array, with the field values implemented in the hash, and the value I want held in the hash:

my $h={ j=>{b=>"some value meaningful to another part of code"}};
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so

return $h->{$l_id}->{$letter_code}
  if (defined $h->{$l_id}->{$letter_code});
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however, this becomes difficult when you have a value

my $h = {j=>{b=>{c=>"some other meaningful value"}}};
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but this

my $h = {j=>{b=>{c=>1}}};
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makes the code mysterious even to me, and I'm inventing the damn thing.

The other problem is that I have a few != clauses; I can't model these in the hash because I don't know the total set of values for that group. TIA