Magento 2 how to access external JS variables and functions in my html template?

I need to access to a javascript module observables and functions so the template does not throws error.

I have my template.html template doing this:

<!-- ko template: "Vendor_ManualShipping/external-template" --><!-- /ko -->

In the js related to that template, of course I have not that functions or observable, because that template is like this:

external-template.html

<div class="manualshipping-container__selectors">
        <select 
        name="region" 
        id="region_checkout" 
        class="input-text" 
        title="region_checkout"
        data-bind="options: availableStates,
                   value: selectedState,
                   optionsCaption: 'Selecciona tu Estado'"
        ></select>
        <select 
        name="municipio" 
        id="municipio_checkout" 
        class="input-text" 
        title="municipio_checkout"
        data-bind="options: availableCities,
                   value: selectedCity,
                   optionsCaption: 'Selecciona tu Ciudad'"
        ></select>

        <a class="action primary continue btn-show" data-bind="click: getPharmaciesInfo" href="#">
            <span translate="'Buscar'"/>
        </a>
    </div>

When I use template.html it throws an error saying availableStates is undefined, of course because I have no availableStates in my js, but then how can I use the javascript of the external template?

I have tried this:

define([
    'jquery',
    'uiComponent',
    'ko',
    'Magento_Checkout/js/model/quote',
    'mage/url',
    'Magento_Ui/js/modal/modal',
    'Vendor_ManualShipping/js/view/external-js'

], function ($,Component, ko, quote, url, modal, manualShipping) {
    'use strict';

This did not worked.

So how then can I have an external template working on another template?

Thanks!