Mash together the garlic, peppercorns, and oregano and combine with orange juice mixture in a large ziplock bag.
Use a knife and poke several slits in both sides of pork roast. Add roast to marinade. Add a few of the orange, lemon, and lime rinds to the bag. Marinade pork for a minimum of 4 hours (longer is better).
Preheat oven to 200 degrees.
Remove pork from marinade and pat dry. Heat olive oil in a dutch oven and brown the pork well on all sides.
