K.F.
My mom had all of ours trained to go in one corner but it takes some work. You simply walk them out on a leash every tme they go and don't let them go anywhere else. After a time, go with them but off the leash, if they try to head elsewhere, shoo them back into the corner. After a time you will be able to send them out and they won't go anywhere else. You will need to scoop the poop every couple of days (my mother made us alway go out with the frigging dog and pick up the poop with a baggie and paper towels, still in therapy) but at least you can do it in the evening instead of demining the area before your kids can play.