Saves from multiple instances of the same effect question

[Banecrow]

So this came up in the game last night and was hoping to get some clarification and if you could give me sources of where I could find this information that would be great. I have not GMed in years so am just getting back into it.

So last night the party ran into a group of troglodytes who have the stench ability. Now the question is, do the PC's have to make a save for each troglodyte's stench to avoid the effect or is it just one save for the entire encounter.

Also another encounter the players ran into giant spiders. One player got poisoned and then bit again, does the player have to make another save or is he just already poisoned? Does the poison effect stack?

If you can please refer me to the rules where these questions are clarified that would be great.

Thanks a lot for the help.

[Zarius]

So, in reference to the poison question, here's a reference for you:
Multiple doses of poison

(My group tends to use the d20PFSRD over Paizo because we don't play society, and we have an issue where the Piazo sight is laid out like Trump crapped into a fan, and now you've gotta clean it all up to get one coherent answer.)

As to the trog inquiry, that's a little harder. There's conflicting data on it. It's CONSIDERED a poison effect, and you get resistances/immunity to poison on it, but it doesn't specify.
Stench

Strictly by RAW, yes. They would have to roll for every instance. HOWEVER, that's a lot of BS rolling, most GMs I've played with, and myself, only do the "roll for all of them" rule for special cases. I mean, a hundred trogs don't stink THAT much worse than one of them. Dragons, however... Dragons are scary mother )(%&#$s. AND, once you pass a dragon's Frightful Presence save, you're immune to it for 24 hours, not true with trogs. Everyone I've played under just does one roll for the stench effect, and just maps where the stench actually is.