Well, I use 3d studio max, it let you to build things like that. In anyway the software to use is not as important in performance as the way you build it, for example, when creating a wall using a box primitive and extruding it, then be sure to use the less amount posible of polygons, using more poligons means more moery usage. Anyway, there are many tips that can be usefull, like not modelling eacd detail but some of them can be included with the textures or even modeling on different files the main structure and merge on the game the small things like desks or things like that.