I believe the registry you are asking about is the C.K.C. (Continental Kennel Club). I don' know much about them, just that they are an open registry and will register purebreds. They aren't as strict as the A.K.C.
I must tell you, your honesty is like a breath of fresh air!

When most of the things you hear about breeders is negitave, you come along and admit that 2 different sires bred your female.

I know it's probably a nightmare for you, but you being honest about it is one of the most positive things I've ever heard. I'm sure some people would just register them with the hope that nothing ever shows up as being wrong. Good luck with whichever way you decide to do it.
Suz