In some cases you may have a 3-Way Pivot table where you wan't to display only the related records in the Resource Show page.

Imagine having a database structure like below:

rooms
    id - integer
    number - string

reservation
    id - integer
    number - string

guest
    id - integer
    name - string

room_reservation_guest
    reservation_id - integer
    room_id - integer
    guest_id - integer

where you want to display the guests with their room number in the reservation show page like below.

In order to achieve this you will need to define a custom intermediate Table Model and it's belongsTo method.

In our case:

namespace App;

use Illuminate\Database\Eloquent\Relations\Pivot;

class RoomReservationGuest extends Pivot
{
    public function reservation()
    {
        return $this->belongsTo(Reservation::class);
    }
    public function guest()
    {
        return $this->belongsTo(Guest::class);
    }
    public function room()
    {
        return $this->belongsTo(Room::class);
    }
}

Next in the Reservation Model define a function which will return the intermediate table model.

public function roomGuests()
{
    return $this->hasMany(RoomReservationGuest::class);
}

After create a Nova resource for the RoomReservationGuest model and define it's fields.

public function fields(Request $request)
{
    return [
        BelongsTo::make('Guest', 'guest', Guest::class),
        BelongsTo::make('Room', 'room', Room::class),
    ];
}

Last define a HasMany field in the Reservation resource for the RoomReservationGuest relation.

public function fields(Request $request)
{
    return [
        // ... 
        HasMany::make('Guests', 'roomGuests', RoomReservationGuest::class),
    ];
}