Way to go Dennis .... I was starting to feel I was the only one answering sscac3d's questions
An alternative way ... which I use all the time ... is to combine the two textures.
So for example, if you have two wall textures A & B combine them so that top half of the new texture is texture A, and bottom half is textureB. Now apply that new texture to the walls object. Use the Texture Cor-ordinate Editor to map one wall to the top half, and the 2nd wall to the bottom half.
If your orginal textures are 'seamless' you can make quite long runs of walls up/down or side by side this way
griff