GroupBy in adapter

I'm trying to work with group By and I can't, my intention is to group the companies within the *poblacion. How can I group so that within poblacion it shows me the companies? it only shows me a repeated item

val works is the list that I receive from the fragment, and what I want is that in the same CardView it shows me the companies that have worked in said population

Poblacion Naquera and within that show me company1 and company2

I hope I explained myself better

This is my Json

{
    "resultsObras": [
        {
        "id": "2",
        "empresa": "company 1",
        "latitude": "xxx",
        "longitude": "xx",
        "poblacion": "Naquera",
        "direccion": "Caseta",
        "obra": ""
    },
    {
        "id": "3",
        "empresa": "company 2",
        "latitude": "xxx",
        "longitude": "xxx",
        "poblacion": "Naquera",
        "direccion": "Pl. Padre Manuel Navarro",
        "obra": "Colector"
    }
       
    ]
}

and this is the adapter

class ObrasAdapter(val obras : List<ResultsObras>) :
    RecyclerView.Adapter<ObrasAdapter.ViewHolder>() {
obras
    private lateinit var mContext: Context

    override fun onCreateViewHolder(parent : ViewGroup, viewType : Int) : ViewHolder {
        mContext = parent.context
        val layoutInflater = LayoutInflater.from(parent.context)

        return ViewHolder(layoutInflater.inflate(R.layout.obras_item, parent, false))
    }

    override fun onBindViewHolder(holder : ViewHolder, position : Int) {

        val groupCity = obras
            .groupingBy(ResultsObras::empresa)
            .reduce { _, groupState, employee ->
                if (groupState.empresa.isEmpty()) groupState else employee
            }
        groupCity.forEach { (company, state) ->
            holder.itemView.tvPoblacion.text = "${state.poblacion}  $company"
        }

        val item = obras[position]
        holder.bind(item)

        holder.itemView.setOnClickListener { view ->
            val intent = Intent(view.context, MapsActivity::class.java)

            intent.putExtras(Bundle().apply {
                putParcelable("OBRAS", item)
            })
            view.context.startActivity(intent)
        }
    }

    override fun getItemCount() : Int {
        return obras.size
    }

    class ViewHolder(view : View) : RecyclerView.ViewHolder(view) {

        private val binding = ObrasItemBinding.bind(view)

        fun bind(clientes : ResultsObras) {
            //println("OBRAS conjunto1 " + conjunto1)

//            binding.tvPoblacion.text = clientes.toString()
//            binding.tvEmpresa.text = clientes.empresa
//            binding.tvObra.text = clientes.direccion
//            binding.tvCometario.text = clientes.obra
        }
    }
}