Aewin and The Great Demo's 20 Step Guide to Importing Rosters
This thread suggests that exporting and importing rosters
might hold the answer, although even the OP doesn't seem sure about the export/import process between universes, which would be what is required. It also looks like it might be somewhat difficult for people without much prior experience of messing with .csv files, too. Perhaps there could be a utility to help with this?
At the moment though everything is purely theoretical, what with any tests being rendered impossible by the apparent death of roster imports in the most recent patch.