Ppx_deriving fields for nested fields or tuple of records

Learning
,
1

I’m trying to solve the problem, where a nested record or a tuple of records could be represented with the same API as the single record.


type alpha =
{
  a1 : int ;
  a2 : float ;
}

type beta =
{
  b1 : int ;
  b2 : string ;
}

type t = alpha * beta

I would like the result of application of deriving to t to look like

  val a1 : t -> int
  val a2 : t -> float
  val b1 : t -> int
  val b2 : t -> string

I would like to avoid writing any boilerplate code, e.g. let a1 = (* extract from alpha, then apply ppx_derive'd function *).

That is, an effect equivalent to

type t =
{
  a1 : int ;
  a2 : float ;
  b1 : int ;
  b2 : string ;
}
[@@deriving fields]

How may I achieve this outcome? Is it possible to issue some parameters to one of the ppxs from ppx_jane? Some other ones?