non-subsumption

Hi everybody, 

I'd like to express in OWL (or in description logic) that two classes are in a non-subsumption relation with each other. This is not as strong as disjointness, as there may be individuals that are members of both classes. In the case of "A non-subsumes B", it says that there exists an individual which is member of B and not of A. Does anyone know if this is possible? 

Thanks in advance,

Jurriaan