How to use "rancid -f file" option?

[Ed Ravin]

I'm trying to set up rancid for the first time.  We already
have a job that fetches configs from our routers and I'd like to
have rancid work with those files.  I see I can invoke rancid with
"-f filename", but it doesn't look like there's a way to fit
that into the "normal" rancid setup with rancid_run.  Do I need to
set up all my batch jobs for those routers separately?