WordPress Loop Group of Three

category-toolbox.php

<?php if (have_posts()) :
					$i=0; // counter
					while(have_posts()) : the_post();
						if($i%3==0) { // if counter is multiple of 3, put an opening div ?>
						<!-- <?php echo ($i+1).'-'; echo ($i+3); ?> -->
						<div class="cf">
						<?php } ?>
					<div class="col3 toolbox">
						<div class="head">
							<h5 style="text-align:center;"><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></h5>
							<div class="aligncenter"><a href="<?php the_permalink() ?>"><?php if(has_post_thumbnail()) { the_post_thumbnail('featured'); } ?></a></div>
						</div>
						<p><?php echo get_post_meta( get_the_ID(), 'ta_post_review_summary', true) ?></p>
					</div>
						<?php $i++;
						if($i%3==0) { // if counter is multiple of 3, put an closing div ?>
						</div>
						<div class="line-separator"></div>
						<?php } ?>

					<?php endwhile; ?>
						<?php
						if($i%3!=0) { // put closing div here if loop is not exactly a multiple of 3 ?>
						</div>
						<?php } ?>

				<?php endif; ?>