from random import choice

teamA = []
teamB = []
teamC = []

players = ["John", "Mark", "Harry", "Jack", "Will", "Joe"]

def allocation(team):
    player_picked = choice(players)
    team.append(player_picked)
    players.remove(player_picked)

while len(players) > 0:
    allocation(teamA)
    allocation(teamB)
    allocation(teamC)

print(teamA)
print(teamB)
print(teamC)