Which idiom corresponds to the Hungarian expression translated 'as if they have agreed ahead of time – although we know that they didn't'?
The Hungarian phrase 'mintha összebeszéltek volna' means 'as if they have agreed ahead of time – although we know that they didn't". How would this appear in English?
Edit: example. Imagine four people turning up in the office in the exact same outfit. It's just coincidence but it looks coordinated. That's when we use this phrase.
Solution 1:
There are over a million hits in a Google search for 'as if in concert', probably making it idiomatic, though I'd say a fixed expression rather than an idiom. This is arguable, as the expression is obviously used metaphorically, for non-musical events.
Only the 'in concert' string is easy to find in dictionaries, but then I'm guessing that most answers here will need the 'as if' qualifier.
in concert ... [figurative]
in cooperation with someone; with the aid of someone.
- Mrs. Smith planned the party in concert with her sister.
- In concert they planned a lovely event.
[McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.]
As if in concert, John, Ali, Jill and Sue turned up at the fancy dress party all dressed as Cousin Itt.
Solution 2:
Different folks may have their own terms. In business environments it's common to hear variations of sentences involving getting or not getting a memo.
For example, if three people come in to the office wearing blue shirts, someone else might say to them or about them, "I guess I didn't get the memo". In turn, the people who did coordinate might say to each other, "looks like we all got the memo". Here's an example from reddit: https://www.reddit.com/r/mildlyinteresting/comments/5vowk5/showed_up_at_work_and_everyone_was_wearing_the/
Outside of a business setting, my experience has been that people make up something on the spot or use something similar to the memo idiom but with emails or text, or they may say "twins". This Quora answer has some examples: https://www.quora.com/What-is-it-called-when-two-people-wear-the-same-clothes-in-English
I'm having trouble finding good documentation of these idioms. If someone can find that, that would be great to add to my answer.