The surveyor that provided the base map for my planting plan used the same tree block to show all the trees on the plan. I would like to make some of these tree blocks 50% transparent to show they will be removed. I put those on a separate layer and made that layer 50% transparent, but the blocks still look and print as dark as the others. Can I change the properties for some instances of one block without changing them on all? If not by layer how do I do it?