woocommerce/templates/single-product/add-to-cart/grouped.php

<?php
/**
 * Grouped product add to cart
 *
 * This template can be overridden by copying it to yourtheme/woocommerce/single-product/add-to-cart/grouped.php
 *
 * HOWEVER, on occasion WooCommerce will need to update template files and you (the theme developer)
 * will need to copy the new files to your theme to maintain compatibility. We try to do this
 * as little as possible, but it does happen. When this occurs the version of the template file will
 * be bumped and the readme will list any important changes.
 *
 * @see 	    http://docs.woothemes.com/document/template-structure/
 * @author 		WooThemes
 * @package 	WooCommerce/Templates
 * @version     2.1.7
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly
}

global $product, $post;

$parent_product_post = $post;

do_action( 'woocommerce_before_add_to_cart_form' ); ?>

<form class="cart" method="post" enctype='multipart/form-data'>
	<table cellspacing="0" class="group_table">
		<tbody>
			<?php
				foreach ( $grouped_products as $product_id ) :
					$product = wc_get_product( $product_id );

					if ( 'yes' === get_option( 'woocommerce_hide_out_of_stock_items' ) && ! $product->is_in_stock() ) {
						continue;
					}

					$post    = $product->post;
					setup_postdata( $post );
					?>
					<tr>
						<td>
							<?php if ( $product->is_sold_individually() || ! $product->is_purchasable() ) : ?>
								<?php woocommerce_template_loop_add_to_cart(); ?>
							<?php else : ?>
								<?php
									$quantites_required = true;
									woocommerce_quantity_input( array(
										'input_name'  => 'quantity[' . $product_id . ']',
										'input_value' => ( isset( $_POST['quantity'][$product_id] ) ? wc_stock_amount( $_POST['quantity'][$product_id] ) : 0 ),
										'min_value'   => apply_filters( 'woocommerce_quantity_input_min', 0, $product ),
										'max_value'   => apply_filters( 'woocommerce_quantity_input_max', $product->backorders_allowed() ? '' : $product->get_stock_quantity(), $product )
									) );
								?>
							<?php endif; ?>
						</td>

						<td class="label">
							<label for="product-<?php echo $product_id; ?>">
								<?php echo $product->is_visible() ? '<a href="' . esc_url( apply_filters( 'woocommerce_grouped_product_list_link', get_permalink(), $product_id ) ) . '">' . esc_html( get_the_title() ) . '</a>' : esc_html( get_the_title() ); ?>
							</label>
						</td>

						<?php do_action ( 'woocommerce_grouped_product_list_before_price', $product ); ?>

						<td class="price">
							<?php
								echo $product->get_price_html();

								if ( $availability = $product->get_availability() ) {
									$availability_html = empty( $availability['availability'] ) ? '' : '<p class="stock ' . esc_attr( $availability['class'] ) . '">' . esc_html( $availability['availability'] ) . '</p>';
									echo apply_filters( 'woocommerce_stock_html', $availability_html, $availability['availability'], $product );
								}
							?>
						</td>
					</tr>
					<?php
				endforeach;

				// Reset to parent grouped product
				$post    = $parent_product_post;
				$product = wc_get_product( $parent_product_post->ID );
				setup_postdata( $parent_product_post );
			?>
		</tbody>
	</table>

	<input type="hidden" name="add-to-cart" value="<?php echo esc_attr( $product->id ); ?>" />

	<?php if ( $quantites_required ) : ?>

		<?php do_action( 'woocommerce_before_add_to_cart_button' ); ?>

		<button type="submit" class="single_add_to_cart_button button alt"><?php echo $product->single_add_to_cart_text(); ?></button>

		<?php do_action( 'woocommerce_after_add_to_cart_button' ); ?>

	<?php endif; ?>
</form>

<?php do_action( 'woocommerce_after_add_to_cart_form' ); ?>