Hey there,
the german translation for "can be" is "Beteiligt in" which would translate to "is part of". So, at the moment the differenct between "is in" and "can be" is not understandable in the german translation. I think, the better translation for "can be" would be "kann in ... sein" and for "can't be" "kann nicht in ... sein". And to clarify the difference to "is in" and "isn't in", I would rename these to "muss in ... sein" and "muss nicht in ... sein"
I am open for better translations by other german speaking users 
