update on nested mongodb document - mongodb

Question

well i am looking for solution where i can update deeply nested mongodb document,
I tried with $ sign but again it has an limitation that it can be used only once which doesn't help the cause. So, is there any way by which i can do this.
my documents looks like
{
"_id" : ObjectId("56fa1a0d8c54754a27ab7a50"),
"name" : "A",
"location" : [
{
"state" : "MH",
"city" : [
{
"cityID" : 11,
"cityName" : "nashik"
},
{
"cityID" : 12,
"cityName" : "mumbai"
},
{
"cityID" : 13,
"cityName" : "pune"
}
]
},
{
"state" : "GJ",
"city" : [
{
"cityID" : 21,
"cityName" : "gandhiNagar"
},
{
"cityID" : 22,
"cityName" : "surat"
},
{
"cityID" : 23,
"cityName" : "ahemdabad"
}
]
}
]
}
,
{
"_id" : ObjectId("56fa1ab88c54754a27ab7a51"),
"name" : "B",
"location" : [
{
"state" : "MH",
"city" : [
{
"cityID" : 11,
"cityName" : "nashik"
},
{
"cityID" : 12,
"cityName" : "mumbai"
},
{
"cityID" : 13,
"cityName" : "pune"
}
]
},
{
"state" : "GJ",
"city" : [
{
"cityID" : 21,
"cityName" : "gandhiNagar"
},
{
"cityID" : 22,
"cityName" : "surat"
},
{
"cityID" : 23,
"cityName" : "ahemdabad"
}
]
}
]
}
,
{
"_id" : ObjectId("56fa1ac98c54754a27ab7a52"),
"name" : "A",
"location" : [
{
"state" : "MH",
"city" : [
{
"cityID" : 11,
"cityName" : "nashik"
},
{
"cityID" : 12,
"cityName" : "mumbai"
},
{
"cityID" : 13,
"cityName" : "pune"
}
]
},
{
"state" : "GJ",
"city" : [
{
"cityID" : 21,
"cityName" : "gandhiNagar"
},
{
"cityID" : 22,
"cityName" : "surat"
},
{
"cityID" : 23,
"cityName" : "ahemdabad"
}
]
}
]
}
So now i want to update the field cityName where name:"A" and cityID:23
for this i have written one query but it has static index,
db.LevelTest.update({"name":"A","location.city.cityID":23},{$set:{"location.$.city.2.cityName":"newCity"}},false,true)
So is there any way that I can write a generic query instead of providing static index of an array element, or any other approach,
or changing the structure is the only solution for this?