Splunk Add-on for Microsoft Windows: How can I set separate indexes by host for incoming Windows event logs?

Hi, I have 3 heavy forwarders which are receiving Windows event logs using the Splunk Add-on for Microsoft Windows. This feeds into Splunk Cloud. Currently all logs are going into 'wineventlog". How can I set separate indexes by host? Say I wanted Windows event logs from "financial_server_1" to go to an index called "financial" and logs from "security_server_1" to go to an index called "security". I believe this can be done with a stanza in C:\Program Files\Splunk\etc\apps\Splunk_TA_windows\local, but how can I seperate this by host name? Thanks, JG