Gemmell identified the fiercely competitive and historic rivalry between Auckland Grammar and King's College as a prime example of the impact of rugby within New Zealand society.
"It's not the only one [example of a big schoolboy rugby rivalry]," said the former Auckland Grammar pupil.
"There are many games like it that are big, that are televised, that have history in New Zealand, but by filming that game, and the obsession around that game, we could showcase to a British audience that this is what kids go through, this is what young men go through on their way to becoming All Blacks.
"They learn about representing their school, they learn about handling pressure, and they learn about what it means to wear a jersey, to have pride, and to represent other people."
"It was actually the people who weren't playing the game, or don't necessarily play the game, or would go along because their brother was playing, or their boyfriend or whatever it might be.
"Our point of contact with all of this was to explain how deeply rugby runs through our country, and not from a masculine, sporting way only, [rather] from a community, connecting way, from who are we as such a young nation, and you really appreciate that when you live in somewhere like the UK.
"Rugby's had its part to play, a really important part to play in developing who we are as a country."
Gemmell went on to highlight that the rugby culture in New Zealand is unmatched in the United Kingdom, where he suggested that there is perhaps more of a "balanced world view".
"There's a huge rugby tradition in the UK, rugby was invented here in the UK, but if you take life in the UK, you can have all of your mates around who play the game and love the game, but the minute you step away from that field, or the minute that you leave a game at Twickenham, you only need to go two or three miles, and rugby disappears from in front of you, from around you, from the television, from the radio, it drifts off into the distance, and other things take its place.
"You might argue that it's a more balanced world view they have over here versus our rugby obsession, but I wasn't making commentary through the documentary whether it was a positive or negative thing, I was more making an observation that it's just part of who we are.
"We started the whole documentary with Sean Fitzpatrick at the grave of Dave Gallagher in Belgium.
"That was a very moving and poignant shoot, it was very powerful to be there, but the point was that the time that the Originals went away, half the Originals were killed in the war ten years later.
"We were such a young country, and, as the historian that we interviewed around that piece said to us, he said New Zealanders were looking for heroes at that point in our history, and Dave Gallagher and his Original All Blacks, they were heroes that we could aspire to as a country full of immigrants at that point who didn't have heroes, who didn't know what it meant to be a New Zealander.
"So if that's your starting point, it's pretty easy to understand how the story and the journey of rugby became so heavily inter-woven with our sense of national identity."