The development of large and complex systems involves many people, stakeholders. Engineeringly speaking, one way to control this complexity is by designing and analyzing the system from different perspectives. For each perspective, stakeholders benefit from means, tools, languages, specific to their activity domain. A Domain Specific Language (DSL) per perspective is such a dedicated means. While DSLs are used for modeling, other means, tools, languages, are needed for other connected activities, like testing or collaborating. However, using together such different types of tools, integrating DSLs into stakeholders' software process, is not straightforward. In this chapter we advance an integration process of DSLs with other tools. To each stakeholder, we propose they have their own DSL with associated graphical editor, operational semantics and generation of scripts for off the shelf simulators for e.g. testing. Additionally to the integrated stakeholders' software process, we introduce a model driven process dedicated to the tool vendor which creates the DSLs and its associated tools. Due to the integration of DSLs into this process, we contend that stakeholders will significantly reduce system construction time. We illustrate the two processes on Telecommunications service construction.