how do i slip loop into group

I’m unsure what you’re after. I think you want 3 posts in each carousel item instead of one, is that right? You can use your $1 counter for this, except you must rename it, you cannot start PHP variable names with a number after the $. Lets say it’s renamed to $x. Use the modulo operator % to get the remainder after integer division. When the remainder == 2, output a closing div tag and a new opening carousel item div.
if ( 2 == $x % 3 ) { echo '</div> <div class="carousel-item">';}
The very first opening div must be before the loop starts and the very last closing div must occur after the loop ends.

the_excerpt() seems to output <p> tags already, so you probably don’t need them in your template code as well, i.e. you don’t need these p tags: <p><?php the_excerpt(); ?></p>

Unrelated to your problem, just something I noticed.

That code does output 3 posts in one carousel item. If they are stacking vertically instead of horizontally, the CSS needs adjustment. Ensure each post’s container (.carousel-caption.text-left) is floated left and its width no more than 33%.

If you can, next time you post code, try to use a version that has line feeds and indents. The version you posted without whitespace is very difficult to analyze.

There’s an extra empty div generated at the end when the post count is evenly divisible by 3. To deal with that possibility, change the if ( 2 == $x % 3) { line to this:
<?php if ( 2 == $x % 3 && ($query->post_count - 1) != $x ) { ?>

Otherwise your code correctly generates 3 posts in every carousel-item div. What purpose does the carousel-inner div serve? Could it be you need a new carousel-inner div every time there’s a new carousel-item div? Instead of it containing all of the carousel-items in one overall div? Confirm by examining a conventional one post per item carousel.

I still suspect the issue might be CSS related. If so, I’d need a live link to the page with the problem in order to advise further about CSS.

Unless you’re sure the carousel-inner is required for every carousel item, I recommend keeping a backup of the current version in case altering carousel-inner turns out to be the wrong call. Handle carousel-inner like this:

<?php if ( $query->have_posts() ) : ?>
	<div id="myCarousel" class="carousel slide" data-ride="carousel" data-interval="5500">
		<?php $x = 0; ?>
		<div class="carousel-inner" role="listbox">
			<div class="carousel-item active">
				<div class="container">
				<?php while ( $query->have_posts() ) : $query->the_post(); ?>
					<?php telegraph_post_thumbnail(); ?>
					<div class="carousel-caption text-left">
						<h1 class="headline"><a><?php echo get_the_title() ?></a></h1>
						<p><?php the_excerpt(); ?></p>
						<span class="float-left text-muted"><?php echo get_the_date( ''); ?></span><span class="float-right text-muted"><?php the_category( ', ' ); ?></span>
					</div><!--carousel-caption-->
					<?php if ( 2 == $x % 3 && ($query->post_count - 1) != $x ) { ?>
				</div><!--container-->
			</div><!--carousel-item-->
		</div><!-- carousel-inner -->
		<div class="carousel-inner" role="listbox">
			<div class="carousel-item">
				<div class="container">
					<?php }
					$x++;?>
				<?php endwhile;?>
				</div><!--container-->
			</div><!--carousel-item-->
		</div><!--carousel-inner-->
	</div><!--myCarousel-->
 <?php wp_reset_postdata(); ?>
 <?php endif; ?>

I also moved the coverage of if ( $query->have_posts() ) : to include the outermost carousel div. It’s very unlikely for it to ever not have posts, but in such a case I’d expect there should be no carousel related content of any sort.

This is the sort of structure you end up with for three posts:

.carousel
  .inner
    .item
      .container
        .thumbnail
        .caption
        .thumbnail
        .caption
        .thumbnail
        .caption
      .end container
    .end item
  .end inner
.end carousel

Do you think there should be a container div for every post or no?