New dog playing too rough with resident dog?

We just introduced a dog to our home where we alredy have one dog. They are getting along, kinda, and I know it will take time. They do want to play together, but they engage in really rough play, biting, standing on hind legs while biting, wrestling. One of the dogs frequently lays on her back and exposes her belly which makes me think she must be accepting her position as the submissive dog. However, the dogs play for about 10 minutes and then get too wound up and end up starting to get truly aggressive and we break them up before a full-fledged fight breaks out. Is this rough play (up until they get too aroused) a good thing? Will it help them acclimate to each other and establish their relationship? Or are we just encouraging them to fight if we allow this type of play?