How to chain serial operations with observables using the rxjs concatMap operator

Question

I am trying to perform a series of chained operations on a database where the starting point is a set of entities that I loop through and for each one I have to execute 3 calls to a service that accesses the database

estudiarConcursos() {
of(...this.data.data.filter(d => d.estudiar == 'Sí'))
.pipe(
  concatMap(
    concurso=>this.dataServiceConcursos.ConcursoEstudiar(concurso)
  ),
  concatMap(
    data => this.dataServiceOfertas.postOferta(this.ConvertirConcursoEnOferta(data))
  ),
  concatMap(
    data =>
       this.dataServiceConcursos.asociarOferta({
        concurso: this.concursoTratado,
        oferta: data
      })
  )
)
.subscribe(console.log)

}

For each iterated concurso I have to do 3 things

1. Update your field Estudiar
2. Create an associated oferta
3. Update your ofertaId field with the ID of the newly created oferta

And my problem is that in the third concatMap I need to access the concurso that is iterating but in data I receive the result of the previous concatMap, that is, the recently created oferta and I don't know how to access the value of the contest with which everything starts

Any idea, please?

Thanks