Setting permission on folders and items of Document Library

Question

Suppose I create a group "XYZ" who has full control on site . I will break permission inheritance of rootfolders (from folder starting with A to J) inside document library "abc" and assign a "XYZ" group with full control permissions to those folders.

My questions are

1. Do other group having full control permission would still be able to access it ?
2. How to make those folders accessible only to XYZ group and not others having full Control permissions.

Answer 1

Those groups will not be able to access the folders if the permission for the folder is broken and only the group "XYZ" has permissions to the folder and rest all are removed.

UPDATE

Sample powershell code:

$folders = $list.Folders
foreach ($spFolder in $folders)
{   
    $PermissionLevel = "PermissionName" ;
    $group = $web.SiteGroups[$GroupName];   
    $spFolder.BreakRoleInheritance($false);
    $roleAssignment = New-Object microsoft.sharepoint.SPRoleAssignment($group);
    $roleDefinition = $web.RoleDefinitions[$PermissionLevel];
    $roleAssignment.RoleDefinitionBindings.Add($roleDefinition);   
    $spFolder.RoleAssignments.Add($roleAssignment);       
    $spFolder.Update();   
}