“Containerize” a eel output inside a cell of a Gtk Gride

Question

I have a Gtk Application using Grid shape to structure widgets, but in one Grid's cell I want to put the rendering of an eel process, like if the eel rendering was a widget.

So, eel just bring the eel.start() command witch launch an independent standalone window.

This is my code:

import gi
import eel

gi.require_version("Gtk", "3.0")
from gi.repository import Gtk


class GridWindow(Gtk.Window):
    def __init__(self):

        super().__init__(title="Grid Example")

        button1 = Gtk.Button(label="Button 1")
        button2 = Gtk.Button(label="Button 2")
        helloworld = Gtk.Label(label="Here where the eel rendering should appear")

        grid = Gtk.Grid()
        grid.add(button1)
        grid.attach_next_to(button2, button1, Gtk.PositionType.BOTTOM, 2, 1)
        grid.attach_next_to(helloworld, button2, Gtk.PositionType.BOTTOM, 1, 2)

        self.add(grid)

eel.init("web")  
eel.start("minimal.html") # ← SEE HERE. The index.html rendering is started in independent standalone windows instead as in widget in the place of “helloworld” Label

win = GridWindow()
win.connect("destroy", Gtk.main_quit)
win.show_all()
Gtk.main()

And this is the rendering:

First I get the eel window

Secondly when I break it, the Gtk Screen

The goal is to make the whole eel content in place of the helloworld Gtk.Label, like if the eel output was a widget. Is it possible? How?