Who would win in a fight a raccoon or groundhog?

It depends on the size of the raccoon and how many Yorkies you are talking about.

Wild animals would rather run than fight. They will fight if cornered and they can do a lot of damage. I would suggest that you try to keep your pet (s) away from confrontations with raccoons as any injury to the dog would cost you money at the Vets, so in effect, you would lose.