[syslog-ng] Filtering Destination by Source

Hello, We have a lot of network logs all being pointed to a central syslog however this is a mix of vendors (Cisco / Juniper / Checkpoint) etc. is there a way of splitting the destination file by vendor type / or source IP address? We ingest this data into Splunk so want to get the source typing right however I am unable to get the sources to point to various listeners and I would prefer. Thanks Peter.