Thanks everyone for your suggestions. I am going to start taking the boys on leash to the area of the yard I would prefer them to eliminate. Hopefully with rewards and repitition they will catch on.
Jenn: Thanks for the suggestion. I'm not overly concerned if they go outside the preferred area where I feel correction is necessary. The boys are really smart and creatures of habit as it is so I'm sure repetition and rewards will more than suffice in helping rejuvinate the lawn