How old were the pups when they were taking from their mother? I apoligize I don't know the story, but 7 weeks old is way young for them to have been separtated for weeks already! Ideally, the pups should have been with their littlermates til they were at least 8 weeks old, so mom could have taught them how to behave, and they could have figured out some of how to socilaize with other dogs before they were separated from their litter.

I would suggest as many play session between your two pups as possible...and let them work through some of the issues. It would also be a good thing, if you were able to get them into a puppy Kindergarten calss so they get a chance to socialize with other dogs.