When mine used to rush the door, I would get between them and the door, then use my body and step towards them to make them get back, telling them 'Back' at the same time. Once they were good at it, I would open the door a crack.... and start over until I could open the door all the way with them sitting 4-5 feet back from the door. The initial training took all of 20 minutes. Now they're pretty good at it... almost 100%.
These videos show the concept: