GroupBy date then by another column within date

I'm building a site that has fixtures that are grouped by date, this bit works fine. But I want to be able to then group the fixtures for a date by the type of fixture, i.e. league or cup, the id is held in the fixtures but the title is in a related table. so the result is like this:

Date 1. League fixtures. Team 1 v Team 2. Team 3 v Team 4. Cup fixtures. Team 5 v Team 6. Team 7 v Team 8.

Date 1 League fixtures Team 1 v Team 2 Team 3 v Team 4 Cup fixtures Team 5 v Team 6 Team 7 v Team 8

So I need some help in doing this last bit of grouping the fixtures by type

this is the query

$fixtures = Fixtures::with('home_team')
        ->with('away_team')
        ->with('venue')
        ->with('result')
        ->with('type')
        ->get();

        $fixtures = $fixtures->groupBy('simpleDate', 'fixture_type');

        dd($fixtures);

current dd of group by date

Collection {#271 ▼
  #items: array:2 [▼
    "2015-09-01" => Collection {#270 ▶}
    "2015-09-02" => Collection {#290 ▼
      #items: array:2 [▼
        0 => Fixtures {#281 ▶}
        1 => Fixtures {#282 ▶}
      ]
    }
  ]
}

Cheers