I quite agree. However, there is another way round this, which is to merge all the walls into a single mesh (outside of Bryce), and then you can select them all in one go, assuming you are happy to have them all the same material and don't want to move them in relation to one another within Bryce. This is what I do. Usually a complex object boils down to about ten different materials, so 100 meshes can be reduced to ten, and everything becomes far more managable.