I have just rescued a 10 month old Irish Wolfhound male. I have had a wolfhound previous to this one so I do know about the breed. This one was kept in a kennel for about 8 to 9 hours a day and is full of energy. We also have a 10 month old chocolate lab and a 3 year old boxer/hound mix. The problem is the wolfie doesnt realize he is as big as he is and he is trying to play with the other 2 dogs, head butting, pawing, etc, but he is hurting the other two and they are becoming afraid of him whenever he comes near and they growl and nip at him, when he just wants to play. He doesnt respond well to the NO command or spraying a shot of water in his face to discipline him. I have tried shaking a can of marbles at him when he misbehaves, but he ignores that also. Any and all suggestions would be very helpful as to what I might do to get this big guy to listen to me. He knows the command for sit and down so he has had some puppy training, but i am trying to figure out how to become the alpha dog in this situation.
Again, please, suggestions would be helpful.

Does he do well with kids? If he does call kids baby constantly and then call you dogs baby. If he associates your dogs with children then he may be less likely to maim them.