Assassin's game mechanics (Please help!)

Is it possible to DM a oneshot with the main motif of an assassin’s game?

More context to the idea: Each PC is given another PC as a target to eliminate throughout the oneshot, before the session, with the goal of leaving one PC left at the end of the game. Ideally no other player would realize the gimmick until during the session. If they fail to complete their task, it triggers a larger combat at the end with the main NPC who tasked the players to the job.

If you’ve seen Thunderbolts, a similar idea as the beginning conflict in the film.

I think it is an interesting idea for a premise of how the party meets up in a campaign, but for a 1-shot I'm not sure how well it works out.

I'm guessing you would tell each player separately that they each had a unique goal of killing one of the other characters. Then through the course of a "normal" one-shot, they would attempt to kill that character, not knowing that each character had a mission to kill one of the other characters.

The main problem comes from the fact that it is hard for the players to do anything secretly. If the group is good enough at not meta-gaming, it might be possible for the players to know what's up, while the characters are not aware that they are all trying to kill off another character, but if the players are supposed to not be in on it, it's going to be given away very quickly. 

If this were online or something and there was a way to privately message the DM without everyone else noticing, it might work, but then you would have to be dealing with secret messages from 4 players and responding to them while also keeping the main story going, all without giving up the twist. 

It seems like a fun idea that will, in practice, very quickly fall apart or have the twist revealed to early. But as a group where the players are all in on it and they just play that their characters have no idea, it could be fun. 

One mechanic you could use is to be open that it is a conflict of assassins and that they are a "team", but they are not allowed to directly assist each other. Then, require that they cannot directly assassinate their targets. Poisoned food, indirect damage, etc. is fine. Each has a set of targets secretly delivered to the player. One of the other PCs is always in one other PC's pool (or perhaps they rotate in after the first 1+ targets are eliminated).

You generate assassination attempts against the PCs but also resolve any PC-on-PC attempts. Having assassination attempts that don't match any of the PCs' attempts will prevent or delay the players from catching on too quickly. At the end, if they haven't figured out the gimmick, you can reveal who killed who.

Some players may not enjoy the PVP and just want to play a game of DnD, so you may want to check if that's okay.

I think it would be best if they tried to kill each other at the beginning and THEN realize they've been set up and go out to get revenge. Spending a one-shot trying to kill each other just doesn't seem to me like the kind of game I'd want to play.