How to use "you" word in a way that suggests it's singular/plural form?

In my mother's language there are two words for "you" - for singular form and for plural one. I want to translate a joke which happen to rely on this particular characteristic of my language.

What words should I use to say e.g. "How can I serve you?"

Is "Ye/Thou" still recognizable or is it too archaic?

Edit: An example: Let's suppose I am a fan of FC Barcelona, the soccer club. Me and my friends are in England to see the Champions League finals. There is a pub with "Manchester United fans only" sign on it and we hear some loud yells coming from inside. I ask my friends if they are willing to go in with me and they say "Yes, sure, we are just behind you. Go!" So I grab my FC Barcelona scarf, go inside and see many MU fans in the middle of the party. Suddenly place goes silent and all the gazes point at me.

That is the point when bartender should say "How can I serve YOU?" in a way that makes me realize my friends are not with me. So, what says bartender?

There isn't a good way of making this singular - the joke only really works in other languages.

The nearest you could get is the barman saying "How can I serve you, sir" which would imply one person, but not really strongly enough to get the joke.

There is a definition in the Douglas Adams book "Meaning of Liff" for the feeling you get when you storm into the Captain's cabin and announce "we are taking over the ship and all the crew are behind me" when you suddenly realise you are on your own.

In some colloquial dialects (Irish, I think), "yourself" can be used to indicate "you" in the singular. "So, how's yourself then?"

In Pittsburgh, they say "yun" and "yuns" (I assume they are contractions of "you one" and "you ones"). Outside of Pittsburgh, well, you're on your own...

Ye/Thou is not appropriate in modern day language (except in highly specialized contexts.)

The best approach would be to add another word, for example: "How can I serve you folks?" or "How can I serve you all?" (Though this latter has tones of "y'all" which is a southern American English idiom.)