There is now, from Toronto to Paris to Copenhagen, an international style of cute, lousy art-house ensemble comedy -- a marzipan mode of bourgeois flippancy that might best be described as ''Chekhov meets 'Friends.''' In Zus & Zo, a Dutch dud that is one of this year's Academy Award nominees for Best Foreign Language Film (the category seems designed to make the American nominees look like masterpieces), a trio of thirtysomething sisters do all they can to prevent their kid brother from getting married, lest he inherit the beachfront hotel of their youth. The brother happens to be gay, which is the linchpin for much higher-sitcom confusion and ''enlightened'' empathy about the issue of real love versus domestic habit. (Guess which side the movie is on?) The title translates, roughly, as ''This & That,'' a confectionary shrug that pretty well sums up the blasé inconsequentiality of it all.