1. A non-transitory computer-readable storage medium storing computer-executable instructions that, when executed on a computing device, cause the computing device to: interact with a graphical model in a graphical modeling environment, the graphical model including a first modeling domain and a second modeling domain; provide a first data signal and a second data signal in the graphical model, the first data signal and the second data signal located in the first modeling domain; combine the first data signal and the second data signal together to form a bus signal in the graphical model, the bus signal located in the first modeling domain; and pass the bus signal to a non-virtual block in the second modeling domain in the graphical model, the passing performed without decomposing the bus signal into the first data signal and the second data signal, the second modeling domain differing from the first modeling domain.