transition block used to create other items PP2P

I have seen on a few other items that do the same as the palette 2 people use the purge or transition block to create other items. These were all done using Prusaslicer. I would like to do the same. There is the option to use PP2P with the palette 2. how can I set it up to not purge or transition into a block but rather into another item? This 2nd item would not have specific colors assigned to it.