group2 :: Eq a => [a] -> [[a]]

group2 [] = []
group2 (h:[]) = [h]:[]
group2 l = aux [] l
               where aux :: Eq a => [a]-> [a] -> [[a]]
                     aux a [] = [a]
                     aux [] (h:t) = aux [h] t
                     aux a (h:t) = if (head a) == h
                                      then aux (h:a) t
                                          else a: aux [h] t