categories.twig

{% extends "_layout" %}

{# Get all the categories to display #}
{% set allCategoriesById = entry.linkCategory.indexBy('id') %}

{# Get all the pages related to those categories #}
{% set allCategoryPages  = craft.entries.section('pages').relatedTo(allCategoriesById).with(['pagesCategory']) %}

{# Group the pages by the categories ID's #}
{% set pagesByCategoryId = allCategoryPages|group('pagesCategory[0].id') %}

{% block content %}

    <div class="row">
        <div class="col W-12">
            <p>{{ entry.title }}</p>
        </div>
    </div>

    {% if pagesByCategoryId|length %}
        <div class="row">

            {# Loop over each of the categories we fetched at the beginning #}
            {% for categoryId, category in allCategoriesById %}
                {# Now loop over all the pages that were grouped by that category's id (if there are any) #}
                {% if categoryId in pagesByCategoryId|keys %}
                    {# you can use {{ category.title }} etc in here too if you need to #}
                    {% for page in pagesByCategoryId[categoryId] %}
                        <div class="col">
                            <p><a href="{{ page.url }}">{{ page.title }}</a></p>
                        </div>
                    {% endfor %}
                {% endif %}
            {% endfor %}
        </div>
    {% endif %}
{% endblock %}