Im Grunde genau gleich:
$ar1 = array( 15,10,20);
$ar2 = array([["MauMau" => 10, "Poker" => 15, "Doppelkopf" => 20],["MauMau" => 5, "Poker" => 10, "Doppelkopf" => 25],["MauMau" => 5, "Poker" => 20, "Doppelkopf" => 5]]);
array_multisort($ar1,SORT_DESC,$ar2[0])...