Log into Usher click Room Reservation Administration
Click on Manage Custom User Groups
Pick my group RoomRes-RTF-Spring2016-Studio- Students or whatever group you want to give access to a room then click on "Add Room"
Choose room you want to give access too and choose the "green" Add Room button
Then click on Room Reservation Administration
Pick the room you want to change the users that can access. Ex: CMB 4.116
Then remove the RTF Student group
That is it now 318 doesn't have access to the studios