[NTG-context] mode dependend character handling

[Henning Hraban Ramm]

(This mail was rejected as spam in my first try, and the reject  
message was catched by my spam filter...)

A happy new year!

I'd like to typeset a text in both German and Swiss German orthography,
i.e. I'd like to expand "s (or the like) to ß in German and ss in  
Swiss German mode,
or even better, automagically change ß to ss in Swiss mode.

This is what I have:
\startmode[swiss]
     \def\S#1{ss\relax}
\stopmode
\startnotmode[swiss]
     \def\S#1{\sz\relax}
\stopnotmode

That forces me to use \S{} in the middle of words, very ugly.
I know this is possible in a more sophisticated way! Please?
(My favorite solution would be to make ß expand to ss in Swiss mode.)

Grüßlis vom Hraban!
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