Personally I disagree with the comment that he is being 'leader' If you have ever witnessed a true alpha dog, they do not behave that way. LOL think of high school, the top popular kids seem to glide through school never having to work at being popular and in control, they know they are cool and never have to flaunt it. Then think of the ones striving to be in control, they are the ones who are nasty, and need to put down others to maintain their station. LOL this is a loose analogy but I find it useful. Kaiden, my alpha male, never growls, or argues over resources, he knows if he wants something its his. I have seen him fight once. (in a house with 2 stud JRTs and multiple intact girls this is really saying something!) He is the calmest, friendliest, most out going guy. This is the picture of the 'leader' There was a long experiment (the only one ever done) on dog behaviour that Dr Ian Dunbar was part of, and that is also what they found-the alpha dog is not the one growling and posturing, that is for the insecure middlemen.
This dog is unsure of its place. I agree with Brandy obedience training is a must, just so you have some control over the house hold.
But my biggest issue is-never ever ever ever (can't stress this enough) leave same sex JRTs loose together. Same sex aggression is 'normal' in JRTs. Even the JRTCA website stress it. No responsible breeder will ever sell a same sex JRT to a person who already has one-unless they are a dog proffesional. I am on many JRT lists, and a couple of times a year someone comes on and is very upset because the one JRT killed the other one when no one was home. The story is almost always the same-they had gotten along for years.
I would be very concerned with displacement aggression. This is when the dogs get so aroused they will turn on eachother. I have witnessed this and it is scary. So if all the dogs were crated when you leave, all would be so much safer.
As for the demand barking. Walk away *every* time he does it. Make sure he never gets rewarded for it. If it is bad, give him a time out for 3 min in a crate.
good luck!