Its not a proper standard to have prod/develop/testing region in a same LPAR. Its ideal to have them in different LPAR's. I understand each LPAR is going to have a different IP address and the same is used for accessing it. Each environment is suited for doing different sets of activities and different sets of people, so having them in same LPAR is not of use. Devl region is for developers and for doing development, Testing region is for testing , e.g UAT (user acceptance testing) and Production is the live one.
Hope the above answers to your question to some extent.