Watch Text::Autoformat at work:

use Text::Autoformat;

my $text = <<EOT;
1. First paragraph text
  i. first sub para text
  iii. second sub para text
      a. first sub-sub para text.
      a. second sub-sub para text.
  iii. third sub para text.
2. Second paragraph text
EOT

print autoformat $text, {all=>1};

__END__
1. First paragraph text
    i. first sub para text
   ii. second sub para text
      a. first sub-sub para text.
      b. second sub-sub para text.
  iii. third sub para text.
2. Second paragraph text
[download]

So it is possible, but considering that Text::Autoformat is a TheDamian module, the reading will not be easy on the eye/brain ;-))