You can build scenarios in the same way as you can for Gettysburg. However, with the SDK we will be releasing a new scenario editor that will make the process much easier.If you can build scenarios with the new game in the same way you can with GB, then yes; I think you could place an objective marker right beside Plancenoit church for example with a need to control it with 1,000 men for 15 minutes and therefore having the church itself right beside it would make it vital for either side to stuff it full of men!
Now if an actual fortified place can be marked as an objective... over to Con20or.
As for the church, you can place your objective marker XZ location inside the bounds of the fortified area. If you look at this video: WL Producer Diary #1 from Matrix at 0:11, you can see the objective marker over the church. That is from one of the battle scenarios.
-Jim