Remove seeds from passion fruit. Mix with 2 cups water and quickly run through blender for about 3 seconds, just to separate seeds from juice. Strain seeds and fibers from juice with a wire mesh colander.
Squeeze juice from oranges. Run juice through colander to remove pulp.
Rinse blender to get out any remaining passion fruit seeds.
Cut the hard ends off of the guavas then chop each into small chunks. Place in blender with ½ cup water and puree until smooth.
Add passion fruit juice and orange juice to guava in the blender and blend for a few more seconds.
Serve ice cold.
I bought a carton of POG to compare tastes, and one of the top ingredients on the store bought is pineapple concentrate! Add ½ cup of pineapple juice if you have it on hand.