There's either a really easy way to do this and I've overlooked it or it's not possible.  These seem to be the only options open to me generally.I would like to add visibility states to a block allowing me to stack floor plans in buildings, selecting the level I'm working at with the parameter.  However, I'm issuing various drawings with separate viewports for each building storey.  Is there a way to select the visible state of my drawing separately in each of the viewports?  I don't want to change visibility of layers, just the visible blocks.Any help would be appreciated.Axel