Additional field in facet result

[Florin Mandoc]

Hi, I have a index that contains products and tags as nested children, 
like below:

{
        "id":"413863",
        "ProductID":"413863",
        "type":"product",
        "MainProductID":"",
        "SKU":"8D68595B",
        "Name":"mere",
        "alltext":["mere",
          "",
          "",
          "test product"],
        "CustomName":"",
        "CategoryID":0,
        "CategoryName":"",
        "MasterCategoryID":"0",
        "MasterCategoryName":"",
        "ShortDescription":"test product",
        "UomID":"",
        "Uom":"dz",
        "UomSize":"0.9",
        "ImageName":"",
        "AllowFractionOrdering":"false",
        "DisplayOrder":0,
        "InternalSku":"8D68595B",
        "PrivateProduct":"true",
        "GroupedProduct":"",
        "ProductGroupID":"-1",
        "UomSizeParentID":"",
        "CustomerSiteID":"4553",
        "CustomerAccountID":"2323",
        "IsAccountProduct":"true",
        "IsVariation":"",
        "Tags":["<TagID>1754</TagID><TagName>ztag</TagName>"],
        "Vendors":["<VendorID>4554</VendorID><VendorSKU>qw</VendorSKU>"],
        "_version_":1518371006298718216,
        "_childDocuments_":[
        {
          "id":"413863_1754",
          "type":"tag",
          "TagID":1754,
          "TagName":"ztag",
          "ProductID":"413863"},
        {
          "id":"413863_4554_qw",
          "type":"vendor",
          "VendorID":4554,
          "VendorSKU":"qw",
          "ProductID":"413863"}]}

I am using this query to get the products and facets for tags:

http://localhost:8983/solr/favsearch/select?q=*:*&wt=json&indent=true&start=0&rows=100&&fl=*,[child%20parentFilter=type:product]&fq=CustomerSiteID:4553&json.facet={tags:{type:%20terms,field:TagName,domain:%20{%20blockChildren%20:%20%22type:product%22%20}},categories:{type:%20terms,field:CategoryID}}

The facets response is:

"facets":{
    "count":15,
    "tags":{
      "buckets":[{
          "val":"vendor 1",
          "count":3},
        {
          "val":"vendor 2",
          "count":3},
        {
          "val":"ztag",
          "count":2}]},
    "categories":{
      "buckets":[{
          "val":-1,
          "count":5}]}}}


Is it possible to get in the response the field TagID also?
Or if I add another facet field for tag ids, like this

"facets":{
    "count":15,
    "tagNames":{
      "buckets":[{
          "val":"vendor 1",
          "count":3},
        {
          "val":"vendor 2",
          "count":3},
        {
          "val":"ztag",
          "count":2}]},
    "tagId":{
      "buckets":[{
          "val":1752,
          "count":3},
        {
          "val":1753,
          "count":3},
        {
          "val":1754,
          "count":2}]},
    "categories":{
      "buckets":[{
          "val":-1,
          "count":5}]}}}

can I be sure that always the first bucket from tagNames corresponds to 
the first bucket of tagId?

Thank you,
Florin