If you really need to hang on to the //gmc regex construct then you could opt to include the regex's as alternatives. Afterwards split the grouped result per regex based on field position in the group.
Update:
- note that the order of the alternatives influences which one will match first each time (and that's what you wanted right?)
- since the total regex is just one expression your program will examine the text only once -> performance gain

See below for an example to get the idea.

#!/usr/bin/perl
use strict;
use warnings;

my $text = <<TEXT;

Title: The Moor's Last Sigh, Author: Salman Rushdie

Title: The God of Small Things, Author: Arundhati Roy

Title: A very special title, Author: varianf varians
TEXT


my @answers;
my $re = qr/Title: (.*?), Author: (\w+) (\w+)$/; # 3 groups here
my $re2= qr/Title: (.*?special.*?), Author: (\w+) (\w+)$/;

my (@MatchAll) = ($text =~ /$re2|$re/mgc);

my (@Match1,@Match2);
for (my $i=0;$i<@MatchAll;$i=$i+6) {
    defined $MatchAll[$i] && push @Match2, $MatchAll[$i..$i+2];
    defined $MatchAll[$i+3] && push @Match1, $MatchAll[$i+3..$i+5];
    }

Output:

$ perl reg.pl

.$VAR1 = [
          'A very special title',
          'varianf',
          'varians'
        ];
$VAR1 = [
          'The Moor\'s Last Sigh',
          'Salman',
          'Rushdie',
          'The God of Small Things',
          'Arundhati',
          'Roy'
        ];
[download]

P.S.: I hardcoded the boundaries for the captured fields to shortcut the coding here. Naturally this part could/should be coded more flexible if you deal with a lot of regex's.