Permissions?

So I have a server up all and also have an Enjin site for it. I'm working on making donor ranks. I made the ranks and setup the shop to sell them(and tested, they work) but I can't seem to get permissions to work right. I have GroupManager, and currently members(Second rank) and up have access to /hat, but I don't want members to be able to have /hat, only the donors and mods and stuff. Does anyone know how to DISABLE permissions?