HIE – I’m not a mumcheh, so I can’t say for certain that “ro’in zeh es zeh” is or is not enough; I just recall that when we had ten people split between two rooms, even when they could see each other, my Rosh Yeshiva would insist that we have a minimum of ten in a single room before he’d allow us to Daven as a Minyan. It could well be that we’re now in a situation where we can be Somech on Shitos that are more Meikil on this – and it could also be that my Rosh Yeshiva was being Machmir on a Shita that is not universally accepted only because it was possible to be Machmir at the time.
an Israeli Yid