Mix the teriyaki sauce, V8 juice, honey, and orange marmalade. When 20 minutes are up, remove the pork from the oven, remove the foil, and with a very sharp knife cut deep slits into the meat. Pour the honey sauce into these slits and over the meat. Slice the unpeeled oranges into ¼-inch crosswise pieces and arrange on the top and sides of the tenderloins. Return the meat to the oven and bake, uncovered, for an additional 15 minutes, or until the orange slices begin to curl. Remove the meat from the oven and let stand for 10 minutes before slicing into medallions. Transfer to a platter to serve.