My neighbor just got a new puppy (terrier) and as we share a yard the puppy needs to be introduced to my two older dogs (both med-large cross breeds). The one older dog met the puppy and it went well; no issues. The second one though is extremely boisterous and rough with the puppy. They have met twice now in a controlled setting and both times puppy was pinned down roughly and examined - no issues here and puppy behaved submissivly; even rolling on her back and baring her underbelly. Both times though this was follower by the older dog proceeding to grab her by the throat (while puppy was on her back) - she was not exactly agressive about it and she did not break skin but it was rough and puppy was yelping. The older dog did not release her until I physically separated them. Now the puppy, who is generally confident and friendly is understandably skittish. The older dog is still very interested in puppy when they hear /see her by my neighbors door and does not appear agressive as much as excited but I'm now not sure how to have them get used to each other without a repeated situation - I don't want to risk traumatizing the puppy any further. Any advice?