Why is it possible to share a file with a group that you do not have access to?

Hi,

I'm trying to figure out if there is a preference that the Super Admin can change to disable file sharing by group to those groups that a given user doesn't have access too. The reason I've created groups is so that we can share things "privately" by individual groups of users. If everyone has the ability to share files to all other groups, whether or not they can see them after, it takes away the security of a document because a user could easily share the file with the wrong group inadvertently. Why give them the option?

Does anyone know of a fix for this?

Thanks,

Maryette