file sharing permissions in child folder

Dear All

I want to Shear the folder like below

MainFolder Folder1 Folder2

i Have 2 folder inside the mainfolder i want every to access mainfolder and folder1 but for Folder2 i want only 3 users to have access to the Folder2

what i do i shear the mainfolder with Everyone FullAccess then i go to the Folder2 i set the permission for only 3 domain users but when i apply this what happen only the 3 users have access to the all folders other users can`t access the Mainfolder and Folder1

i am using Windows 7 Pro with Domain Server 2008 r2

Thanks