excluding some groups in posting styles

[Sebastien Kirche]

Hi,

while using the posting styles, i know how to define a rule for every group,
a branch like "fr.*" or a specific group.

I did not find with the manual if i can exclude a specific group.
Let's say  i would define a  header for all  "fr.*" but not for  "fr.test" :
would it be possible with a regex trick ? 

Thanks for advice.
Sébastien Kirche