groupBy : 'datetime'

Hi, I'm trying to groupBy a datetime but what happens is that all my datetime's are different and I get different groups by each minute.

How can I change the datetime when doing the ng-repeat ?

My code:

```

• 
  
  {{key | date: 'MMM d, y'}}
  
  






• 
  
  
  
  
  {{notification.datetime | date : 'HH:mm'}}

  
  {{notification.title}}
  

  
  

  
  

  
  
  
  

Thank you!