how/when do u tell play partners ur pregnant

im 9 weeks, not telling family til 12 but we have a regular couple we see in 2 weeks and our annual hotel weekend in 5... do i tell them before, at the meet, after the 12 week scan. on one hand its their business if were playing with them, on the other hand its... my body, my news. and what if i miscarry between now and the 12 week, do i then have to un-tell. how have ppl handled the messaging here. its such a weird situational etiquette no ones written about