[syslog-ng] Cisco boxes and syslog-ng

Hello, I have different sets of devices, dslams, nas, core routers, customer routers,... i want to syslog them all, i want to make each device log to a file separately to ease it up for NOC, someone suggested syslog-ng, frankly, i got quickly lost in its docs, the syntax isnt clear, how can i just easily specify to let it log per source into different files ? Regards, Joost