$VAR1 =
{
   '200210014 200210105' => 
    [ 
       "ABC Corp. / 1 / some text description",
       "XYZ Ltd. / 1 / some text description",
       "CDC Inc. / 1 / some text description",
    ],
   '200211011 200212053' =>
    [
       "ABC Corp. / 2 / some text description",
       "XYZ Ltd. / 2 / some text description",
    ],
   '200323021 200331234' =>
    [
       "ABC Corp. / 3 / some text description",
    ],

   etc...
}

##</code><code>##

while (<FILE2>) 
{
   my ($key2,$data) = split(/,/, $_, 2);

# use grep to do the "join":
   my @match_keys = grep { my ($sid,$eid) = split(/ /,$_);
                           $key2 >= $sid and $key2 <= $eid } keys %VAR1;

   foreach my $matched_range ( @match_keys ) {
      my @matched_data = @{$VAR1{$matched_range}};
      # do something with @matched_data
   }
}