Is there any numpy group by function?

Is there any function in numpy to group this array down below by the first column?

I couldn’t find any good answer over the internet..

>>> a
array([[  1, 275],
       [  1, 441],
       [  1, 494],
       [  1, 593],
       [  2, 679],
       [  2, 533],
       [  2, 686],
       [  3, 559],
       [  3, 219],
       [  3, 455],
       [  4, 605],
       [  4, 468],
       [  4, 692],
       [  4, 613]])

Wanted output:

array([[[275, 441, 494, 593]],
       [[679, 533, 686]],
       [[559, 219, 455]],
       [[605, 468, 692, 613]]], dtype=object)