The globalization and the rapid development of information and communication technologies encourage organizations to work together. In software development, many works have emerged to support this cooperation using different tools and methodologies. Most of them focus on the design-stage concerns. However, very little works have dealt with cooperation during the early stage of software projects, namely Requirements Engineering (RE), despite the importance of this stage for the failure or the success of software projects. There exist different kinds of approaches to support the RE process in different contexts, based on models such as goal, viewpoint and scenario oriented. Each of these models relies on concepts which differ from one model to another. One of the difficulties for organizations that intend to work together in the upstream phases of software projects is summarized by the following question: What is the most appropriate approach every partner has to adopt? In this paper, we propose a translation process between RE models in order to ensure that organizations with different types of RE backgrounds and methodologies can work together to achieve their objectives while still using their own approach. The translation is performed using a unified meta-model issued from a semantic process of computing similarities between concepts of RE models.