Complex sentence: The war against Walker would continue, joined now by the armies of other Central American countries under the overall command of General Mora, focused on cutting the men and weapons flow to the filibusters cutting the transit route.
Split into simpler sentences: The war against Walker will go on, joined now by the armies of other Central American countries under the overall command of General Mora. The Costarricans now focused on cutting the men and weapons flow to the filibusters cutting the transit route.