This paper describes a middleware to integrate external tools from third-party providers in the PoEML e-learning platform. PoEML is a modelling language that enables the modelling collaborative learning units. This middleware enables us to include tools from third-party providers in the environments provided to support collaborative learning activities. The main feature of this solution is that the e-learning platform can control the tools' operation in several ways by taking to account issues such as authorising users, creating instances, transferring data to and from the tool, assigning permissions to users, and subscribing to events. This paper illustrates the third-party provision of a special kind of tools in the context of the GameTel project: educational games.