Here’s my solution -
{% set blog_one_posts = blog_recent_posts('8759379468', limit=6) %}
{% set blog_two_posts = blog_recent_posts('8759379470', limit=6) %}
{% set blog_three_posts = blog_recent_posts('5787859864', limit=6) %}
{% set rec_posts = (blog_one_posts + blog_two_posts + blog_three_posts) | sort(true, false, 'publish_date') %}
{% for rec_post in rec_posts %}
{% if loop.revindex >= 6 %}
<div class="col-lg-4 col-md-6 col-12 {{ rec_post.parent_blog.slug }}">
<div class="story-block">
<div class="story-thumb">
<a href="{{ rec_post.absolute_url }}">
<div class="thumb-height"></div>
<div class="thumb-img" style="background-image: url('{{ rec_post.featured_image }}')">
<img src="{{ rec_post.featured_image }}" alt="">
</div>
</a>
</div>
<div class="story-text">
<div class="author-icon">
<img src="{{ rec_post.blog_author.avatar }}" alt="">
</div>
<div class="author-name">
{{ rec_post.blog_post_author.display_name }}
</div>
<a href="{{ rec_post.absolute_url }}">
<h4>{{ rec_post.name }}</h4>
</a>
<div class="summary">
{{ rec_post.post_summary }}
</div>
<a href="{{ rec_post.absolute_url }}" class="read-more">Read more <i class="fa fa-angle-right" aria-hidden="true"></i></a>
<div class="blog-name">
<hr>
<a href="{{ rec_post.parent_blog.absolute_url }}">{{ rec_post.parent_blog.public_title }}</a>
</div>
</div>
</div>
</div>
{% endif %}
{% endfor %}