1. A computer-implemented method in a graphical modeling environment, the method comprising: providing a control initiator, where the control initiator provides a control signal to a control signal splitter; providing a first subgraph in the modeling environment, where: the first subgraph includes one or more blocks, and the first subgraph is connected to the control signal splitter; providing a second subgraph in the modeling environment, where: the second subgraph includes one or more blocks, and the second subgraph is connected to the control signal splitter; executing the first subgraph on a first thread to produce a first result when the first subgraph receives the control signal from the control signal splitter; and executing the second subgraph on a second thread to produce a second result when the second subgraph receives the control signal from the control signal splitter.