Remove the zest of 2 of the oranges with a zester; or pare finely with a vegetable peeler, then cut into thin julienne strips. With a very sharp knife, cut off the skin and outside membrane of all the oranges, so you have glistening orbs of golden pulp. Do this over a bowl to catch escaping juice. Choose a saucepan just large enough to hold 2 oranges at a time and put in the escaped juice and remaining ingredients. Dissolve the sugar and simmer for 5 minutes. Submerge 2 oranges at a time and cook just long enough to warm them through about 3 minutes. If they bob up, place a small weighted saucer over them. Remove to a serving dish and continue with the next pair until finished. Boil to reduce the syrup by half, drizzle over the oranges, and chill.