<?php if (have_posts()) :
    global $post;
    switch_to_blog(1);
    $main_blog = get_posts('numberposts=');
    restore_current_blog();
    $laliga_blog = get_posts('numberposts=');

    $postsetx = array_merge($main_blog, $laliga_blog);
    foreach($postsetx as $set)
        $setsort[] = $set->post_date;
    array_multisort($setsort, SORT_DESC, $postsetx);

    foreach ($postsetx AS $post): setup_postdata($post); ?>