Most of the electronic payment proposals found in the scientific literature are focused on a traditional two-domain business model: customer and merchant. However, an enhanced payment model with an intermediary entity could be considered, with the goal of providing additional advantages for the parties in the e-commerce scenario. In this article, we will show the utility of intermediary inside the payment process describing a service of centralization of the payment system (different to a gateway, TTP or connection broker) in a multi-party payment scenario. We illustrate how this service improves Internet selling applications security, which currently need an effort for facing the weaknesses of the different payments models.