The recent rapid growth of the parcel delivery market has led to a rapid increase in the volume of traffic in urban logistics centers. Excessive competition among courier companies and a lack of logistics infrastructure in urban areas have seriously reduced service quality and profitability and have led to traffic congestion in urban areas as well as environmental problems. This study develops a model for integrating services among more than two courier companies for the same service area by proposing a way to design and assign routes for luggage delivery to each participating company. We verify the results of the proposed integration and cooperative operation model by comparing performance indicators (including total cost) between two routing approaches, the dynamic and fixed models, based on the demand pattern. The proposed model may enable a reduction in traffic congestion and environmental problems caused by courier services in urban areas. It may also address the profitability problem caused by the overheated competition in the courier business.