im not 100% sure, but i think its not possible
but what you could do is load them into a sampler in reason, and then export it as an audio file, and cut it afterwards(if you leave space after, etc. )in some other program...if you get what i mean
this wll of course take some time if theres many you want, but this is what i do :)

i like reason a lot, been using it for 2 years... though it sucks that theres still no VST support