It is not that simple I suppose. But ikegami code works great.

my $Line = "1243 That will efficiently match a nonempty group with mat
+ching parentheses two levels deep or less.";

if ($Line =~ /^(?!.*\bgroup\b)(\d{4}) ([^.]+?[.\!\?])$/){
    print "$1\n$2\n"; #Does not print
}
elsif ($Line =~ /^(?!.*\bgXroup\b)(\d{4}) ([^.]+?[.\!\?])$/){
    print "$1\n$2\n"; #Prints
}
[download]

Though it solves my original query just wondering if it is possible to check the word in the second group of (). Thanks ramprasad27 for the "\." point. I didnt know that earlier.

-Dominic