If you're deploying to multiple servers with the same deployment manager, you must give each WDP configuration a unique "Application Name" for the job.
For example, if you are deploying to DEV & QA, you can use application names like "myapp-dev" and "myapp-qa". This will allow you to deploy the same context root ("/myapp" for example) on both servers, regardless of whether the is a cluster or a single node in either DEV or QA.