Sometimes it is not desirable to have more than one process use the same mailbox. For example, when a program connects explicitly with another process across a network, the program uses a mailbox both to obtain the data confirming the connection and to store the asynchronous messages from the other process. If that mailbox is shared with other processes in the same group, there is no way to determine which messages are intended for which processes; the processes read each other's messages, and the original program does not receive the correct information from the cooperating process across the network link.