Yes possible, just tell WordPress to use RAND()
SQL sorting when passing rand
in orderby
parameter:
add_action( "pre_user_query", function( $query ) {
if( "rand" == $query->query_vars["orderby"] ) {
$query->query_orderby = str_replace( "user_login", "RAND()", $query->query_orderby );
}
});
Now you can use:
$users = get_users( array(
'meta_key' => 'last_name',
'orderby' => 'rand',
'number' => 3 // limit
));
print_r( $users );
Hope that helps.