my @groups = qw'[a-zA-Z]+ \d+ \s+';
my $matcher_pattern = join('|', (map {"($_)"} @groups, '.'));
my $pattern = '';
MATCH: while ($string =~ /$matcher_pattern/g) {
     no strict 'refs';
     for my $index (1.. scalar @groups) {
         if ($$index) {
             $pattern .= $groups[$index - 1];
             next MATCH;
         }
     }
     $pattern .= quotemeta ${scalar @groups + 1};
}
$regex = qr/$pattern/