Another way:
1st Round
One person on winner's team goes to kill someone on Pirates (using the first gold that comes up). Then when all the gold comes up, the pirate kills that port royal player (taking all credits). Then the winner and the remaining player line up and the winner takes all of the credits.
2nd Round
Same way as before except: the remaining player and winner get at a distance and the remaining player fires first, as soon as the winner hears "shoot!" or sees gold, they shoot back (this has to be done quickly)
3rd Round
Refer to Round 1. The "shoot and heal" method can be applied here if necessary.