It would be quite a task to accomplish but I'm sure it can be done DonWON.
The "door" would just be a dynamic entity that looks like a door. Not a segment.
The zombie approaches the door and then when it is within a certain distance of the door an animation (attack animation) is initiated that makes the zombie looks like its tearing down the door. An etimer can be used to deduct x amount of health from the "door" entity. Once the "door" reaches 0 health it's destroyed.
I'm at work at the moment, but I'll give it a bash and see what I can do.
Landman