Parent - child data in oic

Content

Hi Experts,

I have two CSVs as attached and both the CSV has a common attribute id. I want to create a REST API that will read both the files, combine the results, and expose as REST API response. Like below:

[ 
{
  "id" : "1",
  "name" : "ankur",
  "contact" : [ {
    "number" : "111999"
  }, {
    "number" : "111888"
  },{
  "id" : "2",
  "name" : "jain",
  "contact" : [ {
    "number" : "222999"
  }, {
    "number" : "222000"
  },{
  "id" : "3",
  "name" : "ankit",
  "contact" : [ {
    "number" : "333000"
  }
   ]
} ]

Can we achieve this somehow? I tried <<xsl:key> but it's not working. Attaching the iar file also.