Add text from custom field to wp_query

Hi everyone,
Is there a way to take the value from a custom field and put it in a wp_query loop?

I need to find a way to get the text from custom field groupip and put it in the wp_query loop to a custom taxonomy group_post. This is what I’ve done so far:

<?php if ( get_post_meta($post->ID, 'grouping', 'on') ) { ?>
	<?php $my_query2 = new WP_Query('group_post=<?php $link = get_post_meta($post->ID, "groupid", true); echo $link; ?>&posts_per_page=-1'); ?>
	<?php while ($my_query2->have_posts()) : $my_query2->the_post(); ?>
	<ul class="group-items">
	<li><?php the_title(); ?></li>
	</ul>
	<?php endwhile; ?>
	<?php }?>

Thanks,
Gregory S.