Custom Project Role- Cannot seperate access to Manage Project Settings and Manage Project Plan when

Summary:

We are trying to create a custom role for a Central Projects Team and the client has determined that this role must have access to Manage Project Settings but not Manage Project Plan. So far, from removing certain priveleges we cannot seperate the access between the two so the role we create either has access to both or neither. How can we grant access to Manage Project Settings without granting access to Manage Project Plan?