I don't think you are reading what I am saying or looking at the example I took the time to provide. In the example there is only one sprite with the bullet behavior. Let me repeat: There is only ONE(1) SPRITE with the bullet behavior!
However, that single sprite object has TWO (2) bullet behaviors on it. I know it isn't as easy as the solution you WANT, but that doesn't exist. And even though this one sounds weird, it DOES work, and does not allow other objects to pass through the walls even temporarily.
Here. Let me draw you a picture:
<img src="https://dl.dropbox.com/u/57899112/DoubleBullet.png" border="0" />
This is a perfect example of why you should post YOUR example so we can help you with YOUR specific case, rather than have to try to guess what you want and have you tell us we didn't guess right.
EDIT: Sorry if I came off as a bit ticked. I don't mean to. If you still have questions, post a simple capx showing what you are trying to do. It will save everyone a lot of time.