In distributed applications, a group of application processes is established and the processes in the group communicate with one another, i.e. intra-group communication. Here, messages have to be reliably and causally delivered to all the destinations. In addition, the processes send messages to any subset of the group at any time. This paper presents an intra-group communication protocol which provides the group of application processes with the selective and causally ordered (SCO) delivery of messages. The SCO protocol is based on the fully distributed control scheme, i.e. no master controller and uses the high-speed one-to-one network where messages may be lost due to the buffer overrun and congestion