The two rooms have to be already created (ie, the command does not create the rooms). You do not want them to be rooms that are part of an existing zone since the house will prevent the main room from being entered. Also, I think it might do weird things to the zedits.
Because of this, I'm currently writing up a fast and trashy little subdivision zone. The rooms are all repetitive and not very interesting. Since an imm has to assign the house anyway, you might want to suggest that the player write up the room descs beforehand and redit the descs at the same time. However, its really just a jumping off point to create your housing projects. It has 38 houses but can be expanded with some basic editing.
You might want to change the descriptions from a subdivision to (for example) an apartment building or condo. I'm also putting in a trigger to take you to an intersection so that the subdivision doesn't really need to be attached. I don't know when it will be available but I expect to have it finished today.
Btw, where is the cost of housing kept?