Creating a doorway

I just started experimenting with building, so sorry for the basic question, but I'm wondering if there's any way to knock an non-centered hole out of an object. I'd like to make a wall with a rectangular doorway without having to build it out of three separate walls. Another way to look at it is that I'd like to have a rectangular hollow section at the bottom of an object rather than in the middle. Make sense?

Thanks,
Sauce

actually the way to do that is to use half a prim when you make the prim hollow cut it in half with cut begin and cut end I believe .25 and .75 to make the opening appear on the bottom.

Awesome. Thanks, BoBo.