Welcome to the forum crixxx!
There is currently no way within the plugins to limit the output to a different range than the range of the mapped parameter.
The Group option is a different type of feature; it determines how the grabbers behave if you have multiple parameters mapped to the same OSC address. More info can be found in the manual: Free Tools Support | Showsync
Typically for more processing of the OSC you can rely on external tools like OSCulator.