I've scanned through the rules to see if there is anything on how saving throws are to be altered if multiple creatures use a common ability with no luck. There are two simimlar situations that I've encountered recently. One is the Boggards' terrifying croak and the other is Troglodytes' stench.
If a party encounters a group of creatures with the same ability, is making multiple saving throws the only way to address all of those creatures using their ability at the same time?
To me, it seams to make more sense for the group of creatures, whether they be croaking or stenching to, in effect, aid each other so that there is one higher DC. However, the Bestiary is written from a single creature perspective for these abilities.
This should be moved to homebrew....
It seems that each creature, by the rules, must be saved against seperately. Since saving throws against stench treat it like a poison, as a house-rule, I'd recommend treating it like a poison and increasing the DC for each "dose" inhaled if you don't want to mess with that many dice, though the DC could explode to being nearly impossible to succeed pretty quickly that way. For a creature that actively uses an ability, such as the boggard, if you wanted a house-rule on how to lessen the rolls involved, I'd look to the shocker lizard as a base; increase the DC by adding to it for each that croaks at the same time, capping at some reasonable value.
Thanks Jackalope,
Your suggestion also fits well with aid other mechanism that already exists for combat. If I take each additional creature as a +2 to the DC and cap it at 20 I think that would be quite resonable.
Cheers,
Geo