The amount of data transmitted on the Internet has been increasing every year as the use of the Internet spreads, and situations that multiple streams simultaneously carry the same data often happen. For example, when multiple users access to a web site at once, their streams contain the same data. If it is possible to merge such multiple overlapped streams carry the same data into a single stream, we can use the Internet more efficiently. In this paper, we propose architecture for merging the same data streams by using reliable multicast transport. Then we applied this architecture to FTP traffic and implemented FTP proxy which transfers data by reliable multicast transport between multiple points. Furthermore, we experimented in FTP proxy and showed that FTP proxy are able to save network bandwidth when overlapped traffic occur.