Use a custom postgresql.conf?

Hello,

I am trying to determine how to get postgres to use a custom
postgresql.conf file that will be located in a directory other than the
default postgresql.conf file. I would like it to be installed via an rc
script so that the database setup can be part of a self-contained install.
I do not want to use symbolic links, and I do not want to edit the
default postgresql.conf file. I am using PostgreSQL version 8.4.4 on Red
Hat Enterprise Linux 6. Currently, I am able to start the database using
the following command, which specifies my custom postgresql.conf file:

pg_ctl start -D /var/lib/pgsql/data -l /var/lib/pgsql/pgstartup.log -o "-c
config_file='/<path-to-custom-config-file>/postgresql.conf'"

Is there a way to set this up so that I can simply call:

service postgresql start

And have the database start using my config file?

Thank you,
Colin