
Lindsay's advice is good but depends how quickly you can get in touch with a reputable behaviourist. In the meantime it is important to remove the opportunities for him to display this behaviour so feed him separately from your other dogs at all times.
When you say he also shows agression to you at mealtimes it's difficult to know what you mean. If he is trying to take YOUR food then keep him shut away while you're eating. If you mean he is being protective over his own food and threatening you as he's eating, I would suggest not putting his meals down to him in a bowl, but gently hand feeding him at the moment - a little at a time throughout the course of the day. If you are wary of that, put his food down and leave him to finish then have a tasty treat in your pocket to offer him as you pick his bowl back up ;)
Preventative measures until such times as you have a behaviourist on board are safer than allowing the problems to become deep rooted. Good Luck and why not join so you can keep us posted on your results and ask further questions or respond to replies.
Regards, Teri :)