How do I create a working Sublime Text 3 plugin alias?

How do I create a working Sublime Text 3 plugin alias?

I'm developing a plugin for ST3 in OSX 10.7.5. How can I keep the repo in
an external directory and create an alias to that repo inside Sublime's
Packages directory so that it works? I've tried creating an alias but the
plugin commands do nothing unless the repo itself is in the Packages dir.