MongoDB lookup 3 collections and nesting the collections

Question

I have 3 collections in a MongoDB instance. I need to join the 3 collections using the lookup operation and I need the collections nested within their respective parent objects.

For example, I have the following mongo tables:

db.opera.insert([
    { "tlocal" : 1, "name" : "A" },
    { "tlocal" : 2, "name" : "B"}
])


db.orders.insert([
    { "olocal" : 1, "name" : "ABC", "tlocal": 1},
    { "olocal" : 2, "name" : "DEF",  "tlocal": 1},
    { "olocal" : 3, "name" : "LMN", "tlocal": 2},
    { "olocal" : 4, "name" : "OPY",  "tlocal": 2}
])


db.olives.insert([
    { "_id" : 1, "name" : "abc", "olocal": 1},
    { "_id" : 2, "name" : "def",  "olocal": 1},
    { "_id" : 3, "name" : "xyz", "olocal": 2},
    { "_id" : 4, "name" : "opq",  "olocal": 2},
    { "_id" : 5, "name" : "lmn", "olocal": 3},
    { "_id" : 6, "name" : "ghi",  "olocal": 3},
    { "_id" : 7, "name" : "jkl", "olocal": 3},
    { "_id" : 8, "name" : "uvw",  "olocal": 4}
])

Now performing a looking on the 3 collections, like this

db.getCollection('opera').aggregate([
    {
    $lookup: {
        from: "orders",
        localField: "tlocal",    
        foreignField: "tlocal",  
        as: "orders"
    }
    },

    {
    $lookup: {
        from: "olives",
        localField: "orders.olocal",    
        foreignField: "olocal", 
        as: "olives"
    }
    },
])

This result is:

{
    "_id" : ObjectId("5ae258de2b13b1c79901defb"),
    "tlocal" : 1.0,
    "name" : "A",
    "orders" : [ 
        {
            "_id" : ObjectId("5ae258e62b13b1c79901defd"),
            "olocal" : 1.0,
            "name" : "ABC",
            "tlocal" : 1.0
        }, 
        {
            "_id" : ObjectId("5ae258e62b13b1c79901defe"),
            "olocal" : 2.0,
            "name" : "DEF",
            "tlocal" : 1.0
        }
    ],
    "olives" : [ 
        {
            "_id" : 1.0,
            "name" : "abc",
            "olocal" : 1.0
        }, 
        {
            "_id" : 2.0,
            "name" : "def",
            "olocal" : 1.0
        }, 
        {
            "_id" : 3.0,
            "name" : "xyz",
            "olocal" : 2.0
        }, 
        {
            "_id" : 4.0,
            "name" : "opq",
            "olocal" : 2.0
        }
    ]
}

{
    "_id" : ObjectId("5ae258de2b13b1c79901defc"),
    "tlocal" : 2.0,
    "name" : "B",
    "orders" : [ 
        {
            "_id" : ObjectId("5ae258e62b13b1c79901deff"),
            "olocal" : 3.0,
            "name" : "LMN",
            "tlocal" : 2.0
        }, 
        {
            "_id" : ObjectId("5ae258e62b13b1c79901df00"),
            "olocal" : 4.0,
            "name" : "OPY",
            "tlocal" : 2.0
        }
    ],
    "olives" : [ 
        {
            "_id" : 5.0,
            "name" : "lmn",
            "olocal" : 3.0
        }, 
        {
            "_id" : 6.0,
            "name" : "ghi",
            "olocal" : 3.0
        }, 
        {
            "_id" : 7.0,
            "name" : "jkl",
            "olocal" : 3.0
        }, 
        {
            "_id" : 8.0,
            "name" : "uvw",
            "olocal" : 4.0
        }
    ]
}

So my question is, is there a way I can nest/group the 'olives' objects array with their respective 'order' objects arrays within the respected opera objects? Something like this:

{
    "_id" : ObjectId("5ae258de2b13b1c79901defb"),
    "tlocal" : 1.0,
    "name" : "A",
    "orders" : [ {
        "_id" : ObjectId("5ae258e62b13b1c79901defd"),
        "olocal" : 1.0,
        "name" : "ABC",
        "tlocal" : 1.0,
        "olives" : [ 
            {
                "_id" : 1.0,
                "name" : "abc",
                "olocal" : 1.0
            }, 
            {
                "_id" : 2.0,
                "name" : "def",
                "olocal" : 1.0
            }
        ]
    },
    {
        "_id" : ObjectId("5ae258e62b13b1c79901defe"),
        "olocal" : 2.0,
        "name" : "DEF",
        "tlocal" : 1.0,
        "olives" : [ 
            {
                "_id" : 3.0,
                "name" : "xyz",
                "olocal" : 2.0
            }, 
            {
                "_id" : 4.0,
                "name" : "opq",
                "olocal" : 2.0
            }
        ]
    }
    ]
}

{
    "_id" : ObjectId("5ae258de2b13b1c79901defc"),
    "tlocal" : 2.0,
    "name" : "B",
    "orders" : [ 
        {
            "_id" : ObjectId("5ae258e62b13b1c79901deff"),
            "olocal" : 3.0,
            "name" : "LMN",
            "tlocal" : 2.0,
            "olives" : [ 
                {
                    "_id" : 5.0,
                    "name" : "lmn",
                    "olocal" : 3.0
                }, 
                {
                    "_id" : 6.0,
                    "name" : "ghi",
                    "olocal" : 3.0
                }, 
                {
                    "_id" : 7.0,
                    "name" : "jkl",
                    "olocal" : 3.0
                }
            ]
        },
        {
            "_id" : ObjectId("5ae258e62b13b1c79901df00"),
            "olocal" : 4.0,
            "name" : "OPY",
            "tlocal" : 2.0,
            "olives" : [ 
                {
                    "_id" : 8.0,
                    "name" : "uvw",
                    "olocal" : 4.0
                }
            ]
        }
    ]
}

Thank you!