Help with Restrict access to admin/user

Hello,
I am building a site where visitors can create accounts.
There a tree roles:
site administrator || office manager || employee.

I am using OG, so I can enable office managers to create and manage their own groups with employee.
Obviously Office managers have permissions to administer users. The problem is that they can administer and user with ID 1.

Using Menu per Role Module I was able to hide the menu links "admin/user", "admin/user/rules" "admin/user/permissions".... from users with role Office manager, so they can't see these links.
But what if someone try to guess the links...., than they are able to edit other office managers and even ID 1 user.

I am using views so the office managers going to see only users in their organic group. (lets say in "admin/user_list" not admin/user/user)
But as administrator I need to be able to have access to "admin/user", "admin/user/rules" "admin/user/permissions"..., but to limit this access only for myself.

Any help will be appreciated!