If you know any of the breeders that you got snakes from, you can ask them about taking your collection when/if you die. That's what I did.
Yes, I have provisions in my will as to what happens to my pets. I've discussed with the various people what I do and do not find acceptable as to re-homing my pets. Mostly I trust the people I am leaving it up to, but there's always a "Make sure you NEVER give any of my dogs to XXX, because she's a wacko!" type thing.