As far as I can tell (I might be wrong!) synchronizing the Curator logics or units doesn't do anything. Grouping them puts them in the same group/side for the role selection screen, though.
For the eventHandler, it has to be added to either the Curator units or more likely the curator logic on the client-side (I just kinda shotgunned it and did both, which didn't break anything), and execute 'curatorLogicName addCuratorEditableObjects [[(_this select 1)],true]' for each Curator's logic on the server-side. Obviously this is for multiplayer, so if you're only doing single-player, disregard locality nonsense.