A national grocery chain has launched an online grocery pickup platform that is growing in popularity. To handle increasing customer demand, the platform uses two separate fleets of Amazon EC2 instances managed by Auto Scaling groups. The first fleet handles incoming customer orders, and the second is responsible for validating and dispatching those orders to local stores. While capturing the orders is fast, the validation and dispatch process often takes longer due to inventory checks and coordination with store locations. No customer order data can be lost, even during scale-in or scale-out events. The system must be optimized for cost and performance during high-demand periods.What architectural change will best meet these needs?