I wouldn't let them work it out on their own, Sharon. They're of a pretty powerful breed and if it gets out of hand, one or both could get badly hurt--or you could get hurt if you try to separate them.
If the issue only seems to be with toys, then I would start by removing the toys from the environment. Until you sort out the issue, they can only play with toys if they're isolated from the other dog.
They'll also need very close supervision. If they'll be home alone I think I'd want to keep them crated or at least separated in different rooms, at least until you can make sure there are no other triggers to the fighting.
I do think that an evaluation by a reputable behaviorist would be a good idea. You need to know how serious a problem this might be before you can take steps to correct it. A professional should be able to steer you in the right direction--just make sure you check references and research the behaviorists in your area before making a decision on one.
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."