Question:
I have activated remote logging and receiving syslog messages from several devices. I want to write a separate log file for each device sending syslog messages. How to achieve that?

Answer:
It is pretty easy. You can use dynaFiles for it. With them, you specify a template as the file name. For each message, the filename is re-generated and the output written to the respective file. Read the config file doc for details, but it basically is:

$template DynaFile,”/var/log/system-%HOSTNAME%.log”
*.* -?DynaFile