Let me introduce you to Tiberian Sun: Tech Level War. It's a mod with a new gameplay tweak, in which you have to build very expensive buildings - the tech centers - in order to level up and have superior buildings and structures and eventually win the battle. However, there are not useless units in the lower tiers.
This building (by now, represented by a place-holder) is the Security Guard Office, it allows you to train Security Guards ONLY IF you capture certain city buildings, like this one. The guards come out of city buildings, while the building will be garrisoned, so it will fire at enemy targets.
If you think you can make a better office, please contact me, I need some help.
NICE :D