Another role overrides restriction in field/category if there are multiple roles

We were implementing new role system for our customer. Basic idea was that we restrict what editors could see. For example, Finnish and Swedish editors can only see categories what are relevant to them. Our original idea was to create roles like "Finnish Editor", "Swedish Editor", "Estonian Editor", etc. and that every role has restricted fields categories they don't need as hidden. However, problem came if there were more than one role. They apply all restricted fields and do not override them like they do in most other platforms. We had to abandon this idea and instead kept the existing Editor Role and created roles like "Hide category A", "Hide category B", "Hide category C". We found out that this is the only way of restricting categories if there are more than one role per user.

I'm requesting that if category/field is restricted in one role and another role is added to user where it is not restricted, it will override the first one.