Make it so you can only hunt marks on your own server and not be able to on others would be a good start, have more open windows for S ranks would be a much better solution, it would reduce the traffic between servers as well and lesser complaints about 'early pulls'

EDIT:
Make the Hunt Achievement alongside with eg. Treasure Hunt account wide as well as fates, and possibly a few other things account wide.

It would make it easier as well as being able to get around on different alts and the likes.