Shuffle group

import random

def transpose(groups):
	# return list(map(list, zip(*groups)))

	result = []
	longest = max([len(x) for x in groups])
	for index in range(longest):
		sub = []
		for group in groups:
			if index < len(group):
				sub.append(group[index])
		result.append(sub)
	return result

def shuffleEach(groups):
	result = []
	for group in groups:
		result.append(random.sample(group, len(group)))
	return random.sample(result, len(result))
		

groups = [[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15]]
print(transpose(shuffleEach(groups)))