if they create it like instance u will not gonna be able to sig and if u make it that ppl have to port everybody will spawn in 1 place so is not posible imo
best mass pk zones back in 1,3 if u go out of the limits of the map u have a lot of flat areas and pk there wuld be nice but they are far away from safe zone so is also a risk buth meh i don't think is posible at all.
Pretty much this. If the instance was free-to-enter (Cave of Sadistic Glee and a few others) then there wouldn't be any restrictions as everyone would be able to enter (including other faction peeps and more than 80 people)
If the instance population was set at 160 (80 each), it still wouldn't solve the problem of other factions entering. Also, this instance would only have 1 mass pk at once. So, if say Artifex and Xpendables are already in the middle of mass pk, Ducks and Salvation won't be able to start theirs until Artifex and Xpendables leave.
For something like this to work, it'll have to be done on a TW-like map and for that you'll need a GM to check if the player is from one of the fighting factions and then port all 160 players.