As information systems grow in complexity, standard process analysis frequently encounters computational bottlenecks. While decomposition offers a scalable alternative, its utility depends on the structural and behavioral properties of the fragments. We identify three prerequisites for reliable decomposition: property preservation (e.g., soundness), valid result aggregation, and hierarchical abstraction. This paper presents IsoNet, a tool implementing a decomposition strategy based on subnets that are independent of the rest of the net, apart from designated entry/exit points. IsoNet automatically identifies fragments that can be independently transformed into workflow nets (WF-net) that inherit soundness and free-choiceness properties. By maintaining consistent WF-net semantics both internally and externally, the tool supports a natural zoom-in/zoom-out workflow that simplifies complicated processes while maintaining a connection to the global model.