How to use pluck() at the request level?

Question

Laravel

Given:
- laravel 5.6
- a model (let's call it A) with a hasMany relationship (let's call it B) to another model. Which has a column structure - id | a_id | key | value
Problem:
Need to retrieve data along with related data via hasMany. And here the problem is that the data received through the connection must first be passed through pluck('value', 'key').
I make the request like this:

$a = A::with('B')->get();
dd($a);

Communication in model A is like this:

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

Is it possible to do this at the request level? Or is there only one option - after receiving the data, loop it and rewrite the data inside the connection via pluck ()?
PS naming is shortened to simplify the semantic load.

Answer 1

This cannot be done not only technically, but also in meaning - there must be models on both sides of the relationship.
You need to add the necessary fields to the selection and "after receiving, twist them in a cycle."