Cut the tops and bottoms off the oranges and grapefruit. Place one of the flat ends on a cutting board and, following the natural curve of the fruit, slice off the peel from top to bottom being sure to remove the white pith. Cut the fruit horizontally into 1/2 inch slices and arrange on a platter. Drizzle any juice that collected on the cutting board over the citrus. Sprinkle with pomegranate seeds and serve.
You can also cover with plastic wrap and store in the refrigerator for up to 1 day. The blood oranges will stain the other fruit so place them on the bottom.