[Help]When is play too "rough"

I have a small 20-pound older female dog. My roommates have 2 male husky puppies. My dog has bounced between ignoring the puppies, trying to play with the puppies, and growling/guarding territory resources. Recently, some of her play has gotten a little rough (I believe she is playing because she bows down, hackles aren't up, rolls over/is submissive, but I think she just gets a little too rough with the small pups (there have been some yelps). How much is ok? Also, any general advice about preventing future aggression/resource guarding/rough play? I'm a little nervous about having two full-grown male huskies around my generally submissive, smaller, female pup; I want to avoid any fights or aggressive behavior. Thanks! via /r/dogs http://ift.tt/2qxXqHM