Thinly slice two of the six oranges and place slices in the bottom of a large pitcher. Add mint sprigs and simple syrup.
Use a cocktail muddler or the back of a wooden spoon to gently muddle the oranges with the mint and simple syrup help release all of the flavors.
Slice the remaining four oranges in half and use a fork to squeeze all of the orange juice into the pitcher.
Add rum, orange blossom water and lime juice to the pitcher then stir.
Fill four glasses with ice then fill 3/4 way with mojito mixture. Top each glass with 4 ounces club soda to serve.
Traditional simple syrup is made with a 1:1 ratio of sugar and water but I didn't find that necessary since I was using juicy oranges that were naturally sweet. If you prefer a sweeter cocktail, feel free to add more sugar to your simple syrup.