I've spent about two hundred years gather duke-level titles in the ERE to create the Kingdom of Greece. Crown authority was raised high enough that I could go for primogeniture, but it's now been lowered. Now my heir holds a gaveldkind dukedom, and when my duke dies, everything goes gavelkind. Is there anything I can do here, short of going to electoral law, and then repeating the annoying process of getting high crown authority?