Hi Giscard,
I wish Personal list option explained above should satisfy your requirement.
If you are intending at globalized way of customizing the F4 help, proper User-Exits should be available in the area of this Masterdata. Unfortunately there are no such User-Exits in my knowledge.
However you may explore this user-exit, with the help of your technical persons, and see whether it is of any help.
ILOM0001
Jogeswara Rao K