It has become common place in business life that companies with related operations engage in a so-called merger in order to benefit from synergies or from combined products and services. In order to handle the complexity of such an endeavour, it is important to utilise a structured approach for finding similarities and contradictions in business process models of both partners. In this paper, we present a suitable procedure for this task. Furthermore, we demonstrate how to identify those specific activities within the overall business processes which must be adapted. In particular, we discuss how such integration can be conducted if the processes of both parties are modelled with Event-driven Process Chains, one of the most popular conceptual business process modelling languages. By the help of a running example we illustrate the join operator for the integration of these models and the interpretation of the result.