Why is my mini american eskimo aggressive with a few of my family members?

I have a 7 month old mini american eskimo that is typically very affectionate and loving but with a select few of my family, all males, he gets very aggressive. I have been trying to figure out some kind of similarity between the relatives but the only thing is that they are male. He barks at them uncontrollably, growls and even on occasion tries to bite. I don't want to have to get him any shock collars or anything like that. Is there anything that I can try?

I found my dog to do a similar thing..and wondered and worried about it until I found out the reason why...the young teenaged males in the family would always play a little more energetically, a little rougher...not hurting my dog, but riling him up. He then would think whenever he saw one of the boys that that was the way he was SUPPOSED to play with them...that interaction is what he was taught and how he then behaved. You could try getting help from the "targets" and do desensitization training to break him of this habit. He could be a little afraid of them also, and be barking a "show" to get them to move away.A shock collar...or E collar as I prefer to call it ...is not a form of punishment as it seems you think. It is just a tool, that may or may not be the right thing to use on your dog. Some people think they are cruel and painful...not true, when used properly. BUt I do NOT recommend using it as a form of punishment to get him to stop barking or growling. Even devotees of e collar do NOT use it when a dog is aggressing. or overly timid.