[syslog-ng]about syslog

hi , I have three machines A B and C which run syslog (not syslog-ng) and they send now their logs toward a remote host S. How is it possible with syslogd (running over S) to manage differents logs from A, B and C according to the log source (i.e create a file for log coming from A , an other file for log coming from B and an other file for C). the machine S, which receive logs is running syslogd , how can it manage the logs coming from the others machines according to their source. If syslog is not able to manage this , can syslog-ng do it?how? thanks