Grouped list with nested hasMany data

What's the best way to make a list from associated models? I've read quite a few people trying to do this, but every solution seems very hacky, if it works at all. For example, with this data:

Code:

crews: [
      {
         id: 1,
         name: 'Steve',
         jobs: [
               {
                  id: 102,
                  type: 'Cleanup'
               },
               {
                   id: 103,
                   type: 'Rails'
                }
         ]
       },
       {
          id: 2,
          name: 'Rick',
          jobs: [
                 {
                    id: 116,
                    type: 'Frame'
                  }
              ]
        }
]

I want a list of all jobs , but group them by crew name.

Code:

Ext.define('Crew',{
     extend: 'Ext.data.Model',
     config: {
            hasMany: {model: 'Job', name: 'jobs'}
     }
})
Ext.define('Job',{
     extend: 'Ext.data.Model',
     config: {
            belongsTo: 'Crew'
      }
})
Ext.create('Ext.data.Store', {
      model: 'Crew',
      storeId: 'crewStore',
      grouper: {
           grouperFn: function(record){
               return record.get('name');
           }
      }
})
Ext.create('Ext.list',{
       store: 'crewStore',
       grouped: true,
})

This loads correctly, but the List will be a list of crews, not jobs. Is the best idea to flatten the data out? That seems to be the most common solution. You can use a custom reader for crewStore, but that defeats the purpose of having associations.

Code:

Ext.define('MyReader',{
      extend: 'Ext.data.reader.Json',
      getResponseData: function(response){
           var data = this.callParent([response]);
           var newData = [];
           for(var i in data){
                 var crew = data[i];
                 for(var j in data[i].jobs){
                       var job = data[i].jobs[j]
                       job.crew_id = crew.id
                       job.crew_name = crew.name
                       newData.push(job)
                  }
            }
            return newData;
      }
}

Is this the only realistic way to do this? I was thinking about making a Jobs store, and have the Crew store load it with data (a master/slave store), but that kills the association, right?