Group elements from list

Hi guys,

I have a list, and i would like to split it using a field value, por example:

• Dictionary
  • startDate_month 6
  • idPeticion 78
  • fechaCreacion 30/06/2020 13:48 GMT+00:00(Fecha y hora)
    
• Dictionary
  • startDate_month 7
  • idPeticion 87
  • fechaCreacion 01/07/2020 9:41 GMT+00:00(Fecha y hora)

I would like to return n list (in this case 2 lists) of elements grouped by the field startDate_month ¿There is any function to do that?