I’ve been trying it (Re: Paris)… I think ultimately you’ll need to get the targets under lockdown and into the safe room, maybe have the fireworks remote so you can dump their bodies over the balcony, and work your way down there to stash them into the bin that’s just below. Unless guards are outside of the Rm -making it extremely hard to get down there in a timely manner. Or it could just be a matter of the timing of when to dump them. I don’t know if their bodies hitting the ground will cause an audio distraction or not.
I’m assuming you allow for KO’s of non-targets (which you can hide), because while I was trying it - I can immediately think of at least 3, but I’m sure there’ll be more.
Edit: Forget dumping their bodies, there’s one NPC in a blue shirt next to some boxes that will see any bodies dumped. If that’s not enough one of the bodyguards comes back to the room. I even had one that stayed behind Victor. That happened 1 out of 4 reloads, so it makes me think of a bug, maybe.