Asterisk 1.8 Basic Setup w/openSIPS

I have an embedded device I have both Asterisk and openSIPS installed on. openSIPS is what a small group of phones register to, but their media/RTP traffic is handled by offsite dedicated Asterisk machines. I’d like to offload some tasks to the Asterisk 1.8 that is local to the embedded device’s openSIPS instance.

Can anyone explain or point to an extremely exhaustive guide or walkthrough to linking together openSIPS and Asterisk 1.8 via sip.conf settings (and whatever else may be necessary)?