G'day jtucker,

Welcome to the monastery.

As you haven't shown any code, it's difficult to know where you're getting stuck with this. For instance, your earlier comment "What I an hung on is the third bullet." [sic] is meaningless to me: it's the first and only time you've mentioned bullets; there are no bulleted lists; how does the 3rd bullet (not shown) differ from the 1st and 2nd bullets (also not shown). In order to get a better answer when you post here, you'd do well to read these guidelines: How do I post a question effectively?

The following skeleton code may help resolve whatever problem you're experiencing. If not, please post any follow-up questions in line with the guidelines I've linked to above.

$ perl -Mstrict -Mwarnings -E '
    my @data = (
        q{1:1 word1},
        q{1:1 word2},
        q{1:1 word3},
        q{1:1 word4},
        q{1:2 word1},
        q{1:2 word2},
        q{1:2 word3},
        q{1:3 word1},
        q{1:3 word2},
        q{1:3 word3}
    );

    my $old_head = q{};

    for (@data) {
        my $new_head = (split)[0];

        if ($new_head ne $old_head) {
            say "> $new_head";
            $old_head = $new_head;
        }

        say;
    }
'
> 1:1
1:1 word1
1:1 word2
1:1 word3
1:1 word4
> 1:2
1:2 word1
1:2 word2
1:2 word3
> 1:3
1:3 word1
1:3 word2
1:3 word3
[download]