Automation systems like power plants or industrial production plants usually involve heterogeneous engineering domains, e.g., mechanical, electrical, and software engineering, which are required to work together to deliver good products and/or services to the customers. However, the heterogeneity of workflows used in different engineering domains makes it hard for project managers to integrate and validate such workflows. A workflow modification language can be used to define the workflows and their modifications; however, further formalization is needed to integrate the workflows. The authors of this chapter propose to extend the Engineering Service Bus (EngSB) framework with a mechanism to integrate and validate heterogeneous workflows from different engineering fields and to link connections between different types of signals in broader sense, including process interfaces, electrical signals, and software I/O variables. For evaluation, they perform a feasibility study on a signal change management use case of an industry partner in the hydro power plant engineering domain. Major results show that the framework can support workflow validation and improve the observability of heterogeneous workflows in collaborative engineering environments.