Apples' Sandobox is supposed to use Apple Event Access Groups, which allow applications to communicate with each other, as described in the WWDC video "Session 206 Secure Automation Techniques In OS X"
However, what is not mentioned (and I could find no reference to it in Xcode 5.x documentation) is how can I find out which Apple Event Access Groups are defined for a specific application.
For example, if I want my App to communicate with Pages (or Photoshop, or Firefox, etc.), how can I find documentation about its Apple Event Access Groups? Where are they defined, and what tool can I use to find them?