Is it possible to load non-default launchd plist files from the /etc configuration file?
To load a launchd job at start up, you need to store your job description plist file in one of two folders:


/Library/LaunchAgents
/Library/LaunchDaemons


Do not edit or store launchd job description files in the /System folder. This folder is reserved for exclusive use by Apple.

You do not need to edit any configuration files.