Solr get facets on each root document - solr

Question

I have a JSON with documents and each document has a few _childDocuments_ I want to search in the parent and get back the parents and facets on each parent separate
Here is a sample JSON
[{
"id": 1,
"productName": "Ford Explorer",
"_childDocuments_": [{
"id": 6,
"color": "blue",
"price": 1000
},
{
"id": 7,
"color": "red",
"price": 2000
}
]
},
{
"id": 1,
"productName": "Ford F150",
"_childDocuments_": [{
"id": 10,
"color": "blue",
"price": 5000
},
{
"id": 11,
"color": "red",
"price": 6000
}
]
},
{
"id": 2,
"productName": "Toyota Highlander",
"_childDocuments_": [{
"id": 8,
"color": "green",
"price": 1200
},
{
"id": 9,
"color": "red",
"price": 2000
}
]
}
]
I want when I search for Ford I should get back all Fords and in each root document get back facets of the children.
Something like this:
[{
"id": 1,
"productName": "Ford Explorer",
"facets": {
"count": 2,
"prices": {
"buckets": [{
"val": 2000,
"count": 1
},
{
"val": 3000,
"count": 1
}
]
}
}
},
{
"id": 1,
"productName": "Ford F150",
"facets": {
"count": 2,
"prices": {
"buckets": [{
"val": 5000,
"count": 1
},
{
"val": 6000,
"count": 1
}
]
}
}
}
]
This is what I got so far
q={!parent+which=type:parent}&json.facet={ "prices": {
"type": "range",
"field": "price",
"start": 1000,
"end": 1000,
"gap": 1000
}
,
}
But this is only returning facets on all child documents.
Thanks in advance