I don't really see how it is going to work in a really fast game like teewars, it seems like it could be problems coding it. Why not make something like warfare in UT3 (haven't played the other so I don't know if warfare exists in them).
For you who don't know what warfare is, its sort of king of the hill, but you take "nodes", and when a node is yours you are able to take the next (and so on and so on, depending the size of the map) and when you own all nodes you can destroy the enemys core (sort of a node too).
This doesn't fit either so why not simply stick with one node, and that you must have it in a time span, but to reclaim it you have to destroy it and then claim it as your own.
The reason for this post is that i think that teewars is too fast for simply "controlling" a hill, I think its gets more even if there is a "node" you have to control in order to win (becouse even if all in your team dies you still have a chance to win if the other team is to slow to destroy the node, and the other way round, if they are really fast to destroy it then they on't have to kill all the enemys).