[xwiki-users] Rights management issue

Hello xwiki users, I reviewed the docs, but I didn't find the right answer, maybe you can help: If a user is in two groups A and B, how can I handle the treatment if it is "allow" in one group and "deny" in the other? Imagine B is the group of experts within a company A, so I would like to have "at least one allow" but I probably have "at least one deny". To overcome this situation at the moment, I must provide admin rights for the experts group, which I am not interested in at all. The second option is to have one user per role, this will lead to inconsistencies and is not preferred too. The thrid is to massively increase the number of groups, for each role combination one own group. This is not an option too. Any ideas? Thx a lot in advance Best regards Pierre