Our aggressive female boxer

Question
Thanks Kristin for being a volunteer - We have a 5yr old spayed boxer (Angelee) and a 7yr old spayed shitzu-westie (Perrer).  Somewhere between age 1&2, Angelee decided to take over the alpha position from Pepper.  At 1st, Pepper but up a good fight but sooon realized she was no match for the much larger and stronger Angelee.  The sprawling was pretty mild and seemed more a power play in the beginning but as time went on it started to get more and more violent and dangerous.  Angelee would grab the back of Peppers neck and shake her wildly, completely off the ground, with no warning.  Nothing we can do will get Angelee to release Pepper until she is ready to.  Then she seems almost remorseful.  We know the aggression is mostly over food and space and have taken as much precaution as possible short of sending one of them to a new home or medicating Angelee.  We have also had numerous visits, in our home, from the dog trainer our Vet recommended.  We don't want Pepper killed, we prefer not to get rid of either one of them, and medication is a last resort.  Do we have any other options?

Thank you so much for any help you can offer.
Cheri

P.S. - Angelee is also aggressive toward other dogs and at one time, picked a fight with three Saint Bernards.  Luckly, the owner of the St's was able to call them off or they would have killed her!

Answer
well what you can do is muzzle the boxer and let her play/meet up with other dogs that she knows(including the shitzu)this will allow her to figure out who is in charge without hurting the other dog

and if it makes you feel better with some dogs,have the other dog muzzled as well

However some dogs,no matter what cannot be cured of dog agression