2 Versions of IDE on Mac - - but use different library?

Arduino Yún and Teensyduino 3.0, 3.1 require different IDE versions on my Mac.

The Teensy 3.0 requires a hacked version of Arduino/libraries/RF24. The Yun requires the standard version (from
http://maniacbug.github.com/RF24.)

How can I manage two IDE versions and have two libraries with same-named objects in them?

I would like to have

Arduino
Arduino/libraries/RF24
Arduino/libraries/RF24_HACKED

and have different sketches pick up the different libraries. Or, is there a better way altogether.

Thanks