anim8or doesn't allow more than 2 faces on the same edge, because otherwise some of the faces would end up being buried inside the mesh, which usually isn't worth it (you wouldn't be able to see them), and i think limiting it to 2 per edge probably also makes it much easier for the program to work out where faces should be put in.
if the object's going to be a building, then it'd probably be better to make it out of several thin cuboid solids, rather than building it from faces in a mesh. real walls and things have thickness, and using cuboids would show that more realistically. and i think it'd be easier, too. anyway, that's how i always make my building models, i find it works quite well for me.
- colclough