How to implement block output of an array from php to html?

Question

PHP

There is a Joomla 3 CMS, a Zoo component (Blog application) and a self-written template on Bootstrap.
Zoo prepares an array of ready-made blocks with content and outputs using echo.
Now everything is displayed in one line:
<div class="row">
and blocks:
<div class="col-md-3">
themselves are divided into lines.
I need to add my block there every nth number of blocks from the array, but my block is twice as wide:
<div class="col-md-6">
than those blocks. And accordingly, adaptability suffers greatly (either empty spaces or a line with one block, etc.)