is it possible to sort posts inside a query based on post value that is in an array – but using the last element of the array?

The code looks something like:

<?php

$mostsharedposts= new WP_Query( 
        array( 'posts_per_page' => 10,
               'meta_key' => 'mashsb_shares',
               'orderby' => 'meta_value', 
               'order' => 'DESC' ) );

while ( $mostsharedposts->have_posts() ) : $mostsharedposts->the_post();

/* Loop here e.g.:*/

endwhile;
?>

meta_value is an array, and I just need the last element of that array. Can I somehow extract that element in a variable, using explode() and end() and sort by that variable or …?
Any idea would be helpful 🙂