Sorting posts (grouped by taxonomy)

I’m working on a directory of design pieces in a collection. The pages are structured showing first a list of designers (using taxonomies and taxonomylist-plugin). After clicking on the designer’s name, a list with correspondent design pieces appears (posts styled as dropdown accordions).

Here’s the structure:

_Designer A
_Designer B
___Item 1 (by Artist B)
___Item 2 (by Artist B)
___Item 3 (by Artist C)
_Designer C

I managed to sort the designers using ksort, however I have no idea how to achieve this for the design items (posts). Please find below the code I’m using:

	{% set tags = taxonomy.taxonomy['designer']|ksort %}
	{% for tag, items in tags %}
		<button class="accordion">
			<h1>{{ tag }}</h1>
		<div class="panel">
			{% for path, slug in items %} 
			{% set post = grav['pages'].get(path) %}
			{% if post.title != null %}
				<button class="accordion sublevel">
					<h1>{{ post.title }}</h1>
			<div class="panel sublevel">
				<p>{{ post.content }}</p>
			{% endif %}
			{% endfor %}

Does anyone have an idea on how to solve this issue? I’m unfortunately not really a coding pro. Thanks in advance!