How to set an array in the Select tag by default?

Question

Laravel

Good afternoon. A question. Project on Laravel. There is a form in it select, where you need to select one of several organizations, but also to be able to select all organizations at once and save it all in the database.
With a choice of 1 organization and saving, everything is selected, saved. But if there are several .. I can not figure out how to do it.
I did it through the usual Select tags, and through the Laravel Collective.
Tell me how to cram all the data into the field and save them.
Controller:

public function create()
    {
        $title = 'Добавление нового терминала';
//        $allOrganization = Organization::all()->where('user_id', Auth::user()->id);

//        dd($allOrganization);
        $allTerminals = Terminal::all();
        $terminalOrganizationId = Organization::where('user_id', Auth::user()->id)->pluck('name', 'id')->all();
        $terminalOrganizationIdJson = json_encode($terminalOrganizationId);
//        dd($terminalOrganizationIdJson);
//        $terminalCashboxId = Cashbox::where('user_id', Auth::user()->id)->pluck('checking_account', 'id')->all();
        return view('client.terminals.create', compact('title', 'allTerminals',
            'terminalOrganizationId', 'allOrganization', 'terminalOrganizationIdJson'));
    }

    //Валидация полей и создание терминала в БД
    public function store(Request $request)
    {

        $this->validate($request, [
            'name' => 'required',
            'organization_id' => 'required',
            'password' => 'required|min:4',
            'confirmPassword' => 'required|same:password'
        ]);

        $terminal = new Terminal();
        $terminal->name = $request->name;
        $terminal->uuid = (string) Str::uuid();
        $terminal->organization_id = $request->organization_id;
//        $terminal->cashbox_id = $request->cashbox_id;
        $terminal->installation_address = $request->installation_address;
        $terminal->acquiring = $request->acquiring;
        $terminal->fiscalization = $request->fiscalization;
        $terminal->password = bcrypt($request->password);
//        $terminal->confirmPassword = bcrypt($request->confirmPassword);
        $terminal->user_id = Auth::user()->id;
            $terminal->save();


        return redirect()->route('terminals.index');
    }

View:

{{--<div class="form-group form-group-add-terminal col-md-11">--}}
                            {{--<label for="organization_id">Организация</label>--}}
                            {{--{{Form::select('organization_id', $terminalOrganizationId, null,['placeholder' => 'Введите организацию', 'class' => 'form-control custom-select'])}}--}}
                        {{--</div>--}}

                        <div class="form-group form-group-add-terminal col-md-11">
                        <label for="organization_id">Организация</label>
                            <select class="form-control custom-select" name="country_id" >
                                <option>
                                {{$terminalOrganizationIdJson}}
                                </option>
                                @foreach($terminalOrganizationId as $item)
                                    <option >
                                        {{$item}}
                                    </option>
                                @endforeach
                            </select>
                        </div>

Answer 1

If I understood correctly, then you need a "many-to-many" relationship, so that you can select more than one organization, you need another plate that will contain the terminal id and organization id.

Answer 2

I understood correctly in the html form you need to draw the output of all organizations? And it turns out only 1?

Answer 3

Make the option "All" and on the server add a handler for it