I would recommend reading the link, it looks like doing multi phased project, you would want to set up views for the phasing and demolish things in different phases, but they should still all be demolished in the project, just at different times. This sounds like if this was done, there wouldnt be multiples: say if showing phase two, a demolished element in phase 3 would know that it is existing in this phase, but demolished in the next. Then use the view prop. to sort the views to the correct phasing. Side note, the explanation to this is in the coimments on the links, not in the body.
http://revitclinic.typepad.com/my_we...-to-phase.html