In an attempt to kill or capture scouts from these tribes, an immediate order is sent out to search the surrounding forests as aggressively as possible. While to some this may seem like paranoia, it is only reasonable to expect the enemy to be capable of our own feats.
Several skirmishing warbands are organized, their purpose being one of utmost stealth. These "disruptors", as they've been called, are sent out to cause as much harm to the trading routes under the enemy's control as possible. Ideally, this would mean no scout, caravan, or messager could get through, but that is likely an impossible goal. Nevertheless, it is made the focus. Meanwhile, the primary armies take advantage of the arid climate to march upon the proxy territories under enemy suzerainty. They are not to be attacked, but rather, cleansed of the tribes that plague them and the league alike.