Mossie wrote:
1914 was the only time that this sort of thing could happen. Not long after, the Lucitania had been torpedoed , gas attacks, the Somme, Paschendale etc. meant there would be no further acts of goodwill towards men !
Not in groups, but there are countless stories of individuals or small groups meeting in no man's land without fighting.
I also talked to a US WW1 vet many moons ago and he told me of him and a pal of his stuck in no man's land during an attack and following counterattack, and sharing a shell crater with three Germans. Neither fought the other. I don't recall him saying that any of them spoke with other's language but that they all held their rifles by the barrel and moved their trigger hands well away from the actions to show no intent. After some time had passed, they all slinked back to their own lines.
Bet that kind of thing happened a lot.
I can't be alone with knowing of the story of some GIs and Germans in 1944 during the Bulge, sharing a cabin over Christmas after agreeing the put a hold on fighting...