If the Sound is in a Mixer, you can select just the branch you'd like to hear. (There isn't a way to jump over a Sound in a signal flow). Or, as you know, you use the Multigrid, which would let you switch between that Sound and pass through. Does your Sound generate a large number of SoundToGlobalControllers?
SelectableSound computes both inputs if the selection control is an EventValue; however, if you can make it into a constant value (or a green variable, set from a Script) it will not compute the unselected branch when it is unselected.