What if user is a member for two groups?!

Hi, I 'm testing this software and I have a question regarding permissions. 
What if user is a member for two groups that assigned to one path and these groups has different permissions?!

Regards.

Any suggestion?

The permissions of the groups will be combined in a way that a denied permission takes precedence over an allow permission. So only the permissions which both groups allow, will be allowed for the user.

This is how most of the permission systems work, it's also the same logic with Windows permissions.