Accidental style like dodecaphonic, but not quite the same

[Rutger Hofman]

Hello list,

I am typesetting a piece by Alban Berg. Its accidental style is like Lilypond's 
dodecaphonic (explicit accidental for each note), but it differs in that 
immediately repeated notes within a bar don't get an accidental. How can I make 
an accidental style that does exactly this?

And related: is there a way to remove one note's explicit accidental even when 
a style prescribes it?

Thanks,

Rutger Hofman
Amsterdam