I am building a caster and looking for ways to increase my caster level. One such way is the teamwork feat Allied Spellcaster. The bonus is untyped so I am wondering if it is allowed to stack with itself if say there were two other casters who had it around me.
The text of Allied spellcaster states that the requirement for getting the benefit of the feat is to be next to an ally that also has the feat. There is no further benefit from having more people with the feat around you as you already met the requirements to get the bonuses.
Also, Untyped bonuses never stack from the same source,unless the source specifically says otherwise. In this case the source would be the allied spellcaster feat.
Usually, a bonus has a type that indicates how the spell grants the bonus. The important aspect of bonus types is that two bonuses of the same type don't generally stack. With the exception of dodge bonuses, most circumstance bonuses, and racial bonuses, only the better bonus of a given type works (see Combining Magical Effects). The same principle applies to penalties—a character taking two or more penalties of the same type applies only the worst one, although most penalties have no type and thus always stack. Bonuses without a type always stack, unless they are from the same source