By Sam Laskaris Writer They’re in it to win it. That’s the thinking of Marko Celic, the general manager of the Six Nations Rivermen, who are preparing this week to once again participate in the Presidents Cup, the national Senior B lacrosse tournament. The seven-team event, which will be held in Oakville, begins this Sunday, Aug. 27, and continues until Sept. 2. All matches will be held at the Toronto Rock Athletic Centre, which despite its moniker is actually in Oakville. “The goal is to win it,” Celic said of the national tournament, which is frequently simply called The Prezzy. “Whenever you go to the Presidents Cup, the goal is to win it. A coach once said if you have a chance to win a trophy, you go for the…