Saving repeated option values in a custom query

If I understood you correctly, you’re basically asking how to group inputs by post ID? If this is the case, you could do something like this

// group by input
name="renewal[<?php echo $post->ID; ?>]"    
// when saving
$_POST['renewal'] // array of input values with each having post_id as key

Or

// group by post ID
name="data[<?php echo $post->ID; ?>][renewal/future-rent/etc.]"    
// when saving
$_POST['data'] // array of arrays, each with post_id as key. post_id specific subarrays have input names as keys and input values as values