Step 1: Cut your pummelo in half. 
Step 2: Cut in quarters.

Step 3: Cut the quarters in half. 
Step 4: Cut the inside section off exposing the individual sections.

Step 5: Seperate the sections from the thick peel.

Step 5 Cont: The peel seperates very easily.

Step 6: Now open up the sections and take out the juice sacks.  Notice that there is very little juice spilled.

Step 7: Repeat steps 2 through 6 for the rest of the Pummelo. 
That is your finished product. 
Enjoy!