
Sounds like teenage behaviour rather than aggression. The easiest way to deal with it outdoors would be to use a headcollar. Much easier to stop them from pulling, easy to stop them from jumping up at people, and if they want to bark at something, you just turn the head away so the eye contact is broken. Obviously if they jump up etc in the house as well, they need to be trained not to.
It's a very, very hard situation to have littermates and really not to be recommended and I wouldn't wish it on my worst enemy to be honest as it is far harder to train two pups than one. (I am currently in that situation, although not by choice -I ended up with one unsold pup so now have 6 month old siblings. This is the second time I have had to keep siblings, I also have a set aged 7 years, so I've been through it twice and it removes so much of the enjoyment of having a pup, with a single pup you get a much closer bond and training is easier.) They do need to be split up very regularly (i.e. on a daily basis) to get individual training. Have you been to any training classes? If you find a good class you will get help with issues such as jumping up at people -it will be easier to start doing it with people that are used to dogs and don't mind possibly being jumped at to start with. Before the issue is resolved, I'd keep the dogs in another room if you have visitors, or even better put on headcollar and lead so you can be sure to stop it. Lots of praise and rewards when they stay with all four paws on the ground.
Also if they are working bred dogs, do you do any form of work with them? Exercise is all well and good, but using their brains will tire a dog out far, far more, so again obedience training etc will help to curb some of that exuberance. :)