Abstract. Web services are business applications having the capability to cooperate within groups to increase the efficiency of serving customers. There have been a number of proposed frameworks aggregating web services for the purpose of enhancing their capabilities with respect to providing the required service. However, the grouping procedure has got less attention. In this paper, we discuss the mechanism web services can use to join existing groups of web services (known as communities). Moreover, we analyze the scenarios where the community is filled up with web services that lied about their capabilities before joining. The objective is to provide and maintain a truthful environment where involving components act truthfully.