SRAM crankarm spider cross compatibilty

[macaroon]

SRAM 11 speed carbon road cranks such as Force/Rival/S9XX series: are the spiders compatible between BB30 and GXP axle cranks?
Are the spiders from the mountain bike cranks of the same vintage compatible with the above road cranks?
The crank arms all look very similar, so I'm guessing they are, but I'd like to know from someone who's swapped between them.
Thanks.