Andrew, sounds like you are used to Revit?
In Vectorworks we show and hide classes in a more traditional fashion (like AutoCAD and ArchiCAD), through class settings.
However if you would like a work flow more like Revits Temporary Hide I would suggest the Visibility Tool, basically you can hide/show objects in a similar class by clicking on them depending on what you have selected in the mode bar. If you would like to show(unhide) something that is hidden press the V key while the Visibility Tool is active to temporarally show hidden objects and click on the ones you want to show again after selecting the correct mode.