Multi-access Edge Computing (MEC) is proposed as a standard framework for the provision and consumption of applications and services in proximity to the end-users of network operators. Proximity has been identified as one of the enablers of the forthcoming 5G, where extreme low latency and large bandwidth will be necessary for some services. However, the need of proximity imposes to network operators the necessity of huge investments in order to distribute computing capabilities towards the access. A less investment intensive approach would consist on sharing infrastructures by integrating MEC environments from different operators or providers. This could open the door to new business models on the one hand, as well as to avoid restrictions in terms of space, energy of regulation, on the other. This paper overviews different integration options by analyzing the MEC framework defined by the European Telecommunications Standards Institute (ETSI) and identifying different architectural alternatives as well as the business and technical aspects that need to be taken into consideration for realizing such integration.