Bondware refactored the legacy content so it is not in the same location as prior versions <11.3.  So if you did dump the runtimes together you would end up with duplicates.  Also if you are going to do it start with the newest Runtime first and work backwards.  That way you have all the latest stuff and when you put in the earlier version using COPY windows will say there are X number of duplicates and give you the option to skip them which is best as you do not want to replace newer files with older ones.  You are still going to have duplicates due to refactoring but can cull them out afterwards.  This should be done in a folder to be added to Poser 11 or 12 and not the main one.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13